JPS58213364A - Small sized electronic calculator - Google Patents

Abstract

PURPOSE:To prevent mis-operation, by providing two display sections, displaying a formula of key input continuously on one display section and displaying a data as the result of operation corresponding to the data of the formula at the same time, for attaining to confirm the relation between the formula and the result of operation at all times. CONSTITUTION:A key input section 2 of a small sized electronic calculator indicates the arithmetic operation such as four rules operations and data entry, and the entry data and the function data based on an inputted desired formula are stored in a key memory 14 and an operation register 15 via a memory input control section 12 sequentially. The formula is displayed on the 1st display section 3A in response to the key operation on the basis of the stored entry data and function data. An operation section 13 performs operation based on the entry data and function data corresponding to the displayed formula and the result of operation is displayed on the 2nd display section 3B at the same time. Further, the operation mistake of the input section 2 is prevented by attaining to confirm the relation between the formula and the result of operation at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small electronic calculator having a function of displaying input calculation formulas.

Conventionally, a small electronic calculator has been developed that has a verification function that can store input calculation formulas and read out the calculation formulas by pressing a predetermined key.

It has been put into practical use. In this type of calculator, for example, if you input the formula r123+456+789=J,
During verification, the stored number data and function data in the calculation formula are stored one pair at a time ([123+J, r456
+J, ...) are read out sequentially and displayed on the display section, and then the final calculation result data "1368J" is displayed on the display section.In this way, the conventional Calculators only display a pair of numeric data and function data on a single display, so intermediate results of calculations cannot be reproduced in the same B# as the input data, which can be inconvenient. In addition, because the display method is one pair at a time, the relationship between the preceding and succeeding terms in the calculation formula and the currently displayed term is unclear.Furthermore, function data is displayed in a multi-digit Japanese character format. Since the function is additionally displayed in some areas of the section, the function display has the disadvantage of being difficult to understand.

On the other hand, even in a small electronic calculator that does not have the above-mentioned verification function, a series of numeric data and function data in a calculation formula entered manually, as well as intermediate results and final results of the calculation, can be displayed simultaneously on the display. This was not done, and it was sometimes inconvenient to know the relationship between the input calculation formula and its calculation result.

This invention was made against the background of the above-mentioned circumstances, and its purpose is to provide two display sections, one of which continuously displays calculation formulas entered manually, and the other. It is an object of the present invention to provide a small-sized electronic calculator in which calculation result data corresponding to the display data of one of the display parts is simultaneously displayed on the display part.

Embodiments of the present invention will be described below with reference to the drawings.

1 to 5 show a first embodiment.

In FIG. 1, a key power section 2 and a display section 3 are provided on the top side of a case 1 of a small electronic calculator equipped with a verification function, and a circuit shown in FIG. 2 is provided inside the case body 1. The electronic circuit components that make up the.

Contains batteries, etc. The key power section 2 includes number keys from 口 to 口, various function keys for the four arithmetic operations such as 9 days 1 ward, 田 etc., reproduction keys 4A, 4B, mode switch 5 and contrast) (CNT) A key 6 is provided respectively. The reproduction keys 4A and 4B respectively read out calculation formulas entered using the numeric keys, function keys, etc. from a key memory (described later) stored in the input category and display them on the display section 3 at the time of calculation. This is the key to reproducing it. In this case, the reproduction key 4A gives a command to reproduce the calculation formula sequentially from the beginning of the formula to the end (forward direction), while the reproduction key 4B gives a command to reproduce the calculation formula sequentially from the beginning to the end of the formula. Give a command to reproduce the data sequentially in the opposite direction.

Mode switch 5i "Off mode in the 0FFJ position, r
Replay mode at REPLAYJ position, rMEMORYj
Set a mode in which the contents of the independent memory are always displayed on the second display section (described later) at the position [DISP,j], and a mode in which only the first display section (described later) is set at the position [DISP,j]. The contrast key 6 is a key for adjusting the display brightness (contrast) of the display section 3 consisting of a liquid crystal display device, and after operating the contrast key 6, when the reproduction key 4A is operated, the display brightness increases according to the number of operations. It becomes darker, and when the reproduction key 4B is operated, the brightness becomes weaker and becomes lighter.

In this case, since the display brightness of the liquid crystal changes depending on the magnitude of the motion voltage, the contrast key 6 and the reproduction key 4
A counter is provided whose contents go up/down according to the operations of A and 4B. Then, a predetermined voltage value is selected from a large number of voltage values and applied according to the count value of this counter, so that, for example, the display brightness changes in 16 steps.

The display section 3 is roughly divided into a first display section 3A on the lower side and a second display section 3B on the upper side. Therefore, the first display section 3A
The second display section 3B has a 9-digit configuration using a 3.times.5 dot matrix display.

As shown in the left end of the first display section 3A and the second display section 3B, x, ÷, 10, -, RP.

Display bodies such as M are also provided to display functions such as addition, subtraction, multiplication, and division, constants, reproduction mode display, and memory mode display, respectively.

Next, the circuit configuration will be explained with reference to FIG. The outputs of the keys and switches of the key-manpower unit 2 are input to the control unit 11 .

This control section 11 is a circuit that controls various operations of this small electronic calculator, and is composed of, for example, a microprocessor. and control command 0. ~O3 is output. The memory input control section 12 receives input from the control section 11 of data corresponding to the output of the key input section 2, as well as operation X result data from the calculation section 13. Then, the input data is input to the key memory 14 or the calculation register 15 according to the memory input control unit 12f'i control instruction O7. The key memory 14 stores calculation formulas entered through key operations, and has a storage capacity of 50 keys per key operation (the number of numeric key and function key operations). The arithmetic register 15 is an X register for storing the arithmetic number and the operand, an A register for counting the number of key operations mentioned above, and the address of the key memory 14 at which the data of the least significant digit of the second display section 3B is stored. The B register indicates whether the data is stored in the memory, and the C and D registers are for temporary storage.

It consists of each register, a register for that song (not shown), and an independent memory. Further, data output from the key memory 14 and the calculation register 15 is input to the memory output control section 16. This memory output control section 16 inputs the input data to the calculation section 13 in accordance with the control instruction 03.
It is output to either the first display control section 17A or the second display control section 17B.

The arithmetic unit 13 receives control commands 0. It executes various calculations according to the following, outputs the calculation result data to the memory input control section 12, and also outputs the result data J of the judge calculation to the control section 11.

The first display control section 17A and the second display control section 17B each have a display register function D2, and each control command 04.0. Accordingly, each display operation of the first display flsaA and the second display section 3B is controlled.

Next, the operation of the above embodiment is shown in FIGS. 3(A) and 3(B).
.

This will be explained according to the flowchart shown in (C).

Now, the calculation formula of the following formula (1) is input into the small electronic calculator of the present invention to perform calculations, and after inputting the calculation formula, the above calculation formula is reproduced on the display section 3 in order to perform a verification. Let's talk about the case.

123+456+789=1368 ・-・(1)
First, the mode switch 5 is set to rREPLAYJ to set the reproduction mode. Next, the numeric key l is operated to input the numerical value "123J. Therefore, the output of the key input unit 2 in FIG. 2 is input to the control unit 11, and
Determine the type of i-operation key and control command 0 with the corresponding content
．． ~0. Output. That is, in this case, the determined number data Ill is input to the X register of the control register 15 of the memory input control section 12. The data "1" in the X register is then transferred to the display register D1 of the first display control section 17A under the control of the memory output control section 16 and displayed at the first digit of the first display section 3A.

To explain the above operation using the chart 70 in FIG. The key is a reproduction key or arithmetic key (number key and data key).

OX, B, mouth function keys) or mouth (clear) key. Since the current key is a numeric key, the process proceeds to step S3, where it is determined whether the operation key is a numeric key or the above-mentioned function key. In this case, since it is a numeric key, the process proceeds to step srs, and numeric data "1" is input to the X register. Next, in step SI6, it is determined whether the reproduction key 4A or 4B has been operated, that is, whether the calculation formula is being reproduced. It's not being reproduced right now, so Step St? It is determined whether or not a part of the data has been deleted by operating the key while reproducing the calculation formula, that is, whether or not it is being deleted.

In this case, since it is not being deleted, proceed to step SHs.
Data "1" in the X register is transferred to display register D, and data in the key memory is transferred to display register D2. Next, the numerical value “1” is displayed in step 814.
" is displayed on the first display section 3A, but since no data has been input into the key memory yet, nothing is displayed on the second display section 3BK. Next, the key sampling process in step S is executed again.

Similarly, when the numeric keys (2) and (3) are operated, the processing of each step described above is executed. FIG. 4 (1) shows the display state of the display section 3 at the time when the above key operations are completed.

Next, when you operate the field key, data r12 in the
3J is transferred to the X register, and data r 123+
J is set in the key memory 14.

Then, this data “123+” is transmitted to the second display control unit 17.
The signal is input to the display register D2 of B and displayed on the second display section 3BK. Further, the eleventh calculation process is executed in the calculation unit 13, and the calculation result data r123J is displayed on the first display unit 3A.
will be displayed.

That is, one or more operations will be explained with reference to the flowchart of FIG. 3. Step S1. After each process of S2, step S,
It is determined that the operation key is a function key. Therefore, the process advances to step s4 and step 811
As in 1, it is determined whether or not it is being reproduced.

Since it is rNOJ, proceed to step $5 and step S.
Similar to IT, it is determined whether deletion is in progress, and since it is rNOJ, the process proceeds to the next step 86. In this step S0, data 1"-123+J is input into the 1st to 4th digits of the key memory 14 according to the contents of the B register (currently "0").Next, in step S, the data number "4" is input. It is counted and set in the A register. Next step S
gK, the number of data "4" is also set in the 9B register, and the display position when displaying the data in the key memory 14 on the second display section 3B is updated. Next, in step S, the data in both the X and Y registers are added, and then in step 51oK, it is determined whether or not reverse reproduction is being performed, that is, whether or not the reproduction key 4B has been operated. In this case, “N
O”, so proceed to step Sll K, then step S
, the same process as step SD+S14 is executed.
Each process is further executed and the process returns to step S1.

FIG. 4 [2] shows the display state at this point.

Next, when data [456J is input using the numeric key, the processing of each step is executed in the same manner as in the case of FIG. 4(1) described above. FIG. 4(3) shows the display state.

Next, when you operate the key, the key memory 14 stores the data "
456+J is further input, its contents are r123+45
It becomes 6+J. Also, by the processing of steps S, , Ss,
The data in the h register and the B register are both "8".

Then, the addition of the data "123J and r456J is executed, so that the display state of the display section 3 becomes as shown in FIG. 4 (4).

Next, input the data l'-789J, and then operate the eye key, and the data ``789=" is further input to the key memory 14, and both the A register and the B register are incremented by +4, and the value becomes ``12". Operation result data r1368J is calculated. The display state of the display section 3 becomes as shown in FIG. 4 (5).

Next, in order to perform a verification, the reproduction key 4A is operated to reproduce the above calculation formula in the forward direction.

At this time, it is determined by the process of step s2 following step s1 that the reproduction key 4A has been operated, and the process proceeds to step S1g, where it is determined that it is the reproduction key 4A in the forward direction. Next, proceed to step $1゜, A,
It is determined whether the contents of the B registers match or not, and since they both match at "12", the process advances to the next step S9 and the B register is cleared.

Then, the process proceeds to step SZt, where the B register is incremented by 1 and becomes "1". The process advances to the next step S22, and data ``1'' at address 1 of the key memory 14 is read out in accordance with the content ``1'' of the B register, and then the process returns to step S2.

In step S2, it is determined whether the data "1" just read from the key memory 14 corresponds to the (6) key, the calculation key, or the reproduction key.
Proceed to. Then, in step s3, it is further determined whether the key is a numeric key or a function key. Since it is now the numeric key, proceed to step s15 and input the data "1".
is input to the X register.

Next, the process proceeds to step S6, where it is determined whether or not it is being reproduced, and since it is currently being reproduced, the process proceeds to step Sll+. Now, since the contents of both registers A and B do not match, the process proceeds to step St+, and the B register increases by +l and becomes "2". Then, from step 5221C, key memory 1402
The next data "2" is read from the address.

For the above data "2", step St + Ss + S+s + S+a y So in the same way as for data "1"
l + Stt is executed, during which the contents of the X register become "12", and the B register becomes "3", and then data "3" is transferred from the key memory 14 in step S22.
" is read out. Then, for this data “3” as well, step Str Ss 1sts l sta l
8111 r SJ” is executed, and the contents of the X register are 1.
'-123J, and the B register becomes "4".

Therefore, in the next step S2□, the key memory 14
Function data "+" is read from address 4 of . Therefore, in step S and later in step S3, it is determined that the data corresponds to the function key, and the process proceeds to step S4. In step S4, it is determined that reproduction is in progress, and the process then proceeds to step S, where result data [123J is obtained through the calculation process. Next, after processing step 816 + stt, step SI
R, 5I41C progresses, and the result data [123j
is displayed, and the calculation formula "1°23" is displayed on the second display section 3B.
+" will be displayed, allowing you to check the key strength.

Next, when the reproduction key 4A is operated for the second time, the same steps as those for the first time are executed, and when the function data "+" is read out, the display section 3 is displayed as shown in Fig. 4 (7). ), that is, the first display section 3A displays 2
The result data "579" of the second calculation is displayed, and the calculation formula r 123+456+J is displayed on the second display section 3B. Also, during this time, the contents of the B register are updated by "8".

The same holds true when the reproduction key 4A is operated for the third time, and when the function data "=" is read out, the display section 3 enters a display state as shown in FIG. 4(8). In this case, since the second display section 3B can only display up to 9 digits, the upper 3 digits of the expression J123J are not displayed. Also, during this time, the contents of the B register are increased to "12".

As described above, by operating the reproduction key 4A three times in this case, the calculation can be performed while reading the equation (1) in the forward direction.

By the way, when starting the calculation in the reverse direction from the state shown in FIG. 4 (8), the reproduction key 4B is first operated once. At this time, after the processing of steps S, , S, it is determined by the processing of step StS that the reproduction key 4B has been operated, and as shown in FIG.
The process advances to step Su in the flowchart of B). In step Sts, it is determined whether the content of the B register is "1" or not, and since it is currently "12", the process proceeds to step Su.
The B register is incremented by 1 and it roars "11". The process then proceeds to step 825, where it is determined whether the data at address 111 of the key memory 14 is function data. Now 11
Since the 1st address data is "9", the answer is "NO" and the process returns to step S23. Then, in step 8231824 r, the contents of the B register are decremented by 1 until the function data "+" at address 8 of the key memory 14 is detected.
825 is repeated three more times, and when the function data "+" is detected in the process of step S25, the process goes to step S26 for eight lines, and the data r8J in the B register is transferred to the C register and protected. Then step 527V
C progresses, the B register is cleared, and steps S, , [
proceed. In step 5l11, the A register is now “
12", so answer "NO") Proceeding to step S2t, the B register is incremented by 1 to become "1", and then in step S2g, the data at address 1 of the key memory 14 is set to "1".
After is read out, the process advances to step S2.

Hereinafter, similar operations are performed in the calculation in FIG. 4 (6) described above, that is, steps St + s, t SJ5 +
SJ6 + 5111 + 821, sa data "2" at address 2 of the key memory 14 is read out by each process, then data "3" at address 3 of the key memory 14 is read out by the same step, and then the same steps are performed. When the 44th address data "+" is read out through the process, the process proceeds from step S to step S4, and after the arithmetic processing in step S, the process proceeds to step 810. This step S. Then, it is determined that reverse reproduction is in progress, and step S! 2, the data “4” in the B register and the data r in the C register
It is determined whether or not they match with 8J. Now rNOJ
Therefore, the process proceeds to step 5lf1. Then, in the same way, until the data in the B register becomes "8" and matches the contents of the C register, the B register is +1 and the data r4J at addresses "5" to "8" in the key memory 14 is added.
, r5J, r6J, and r+J are sequentially read and determined. After reading the function data "+", the process goes to step SI2.

When it is determined that the two images match, the process proceeds to step SI3, and further the process proceeds to step 814.
The result data "579" is displayed on the display section 3A, and the calculation formula "123+456+" is displayed on the second display section 3B as shown in FIG.
9) is displayed.

Furthermore, when the reproduction key 4B is operated once more, steps s, l St + 5lll + s2s are performed in the same manner as above.
l After each process of S24 y S25, the key memory 14
Step 823 + su while decrementing the B register by 1 until the function data "+" at address 04 is read.
tS2! 1 is repeated, and when it is determined in step S that the function data "+" has been read, the process proceeds to step 8, and data "4" is stored in the C register.
is set. Then, the B register is cleared from steps S and rK, and the following steps are performed.

Step S + o + Stt y Su * St w
Ss r Sts y 8+a r See r”
(By repeating D, the B register becomes ``4'' and the function data ``+'' is read, then steps s, ,'s, from the supply block SS, S,.+812 r
According to each process of SO3 + SI4), Figure 4 (10)
As shown in the figure, the first display section 3AIC of the display section 3 displays result data l'-123J, and the second display section 3B displays the calculation formula r123+j.

Next, the operation when deleting a part of the calculation formula being reproduced will be explained with reference to FIG. When the state described in FIG. 4 (7) is reached, that is, when the calculation formula r123+456+J is displayed on the second display section 3B as shown in FIG. 5 (1), the second term 1' -456+J is deleted and the expression [543+J' is inserted in its place. The contents of the A register and B register are r42 J and r8, respectively.
It is J.

In the state shown in FIG. 5 (1), when the key is operated, the operation of the key is determined in step S and step S2, and the process proceeds to step 82G in FIG. Data "+" is cleared. Next, in step S, the data in the key memory 14 is shifted to the right by one digit, and the cleared data area is filled.

Next, in step 831, the Dh register is decremented by 1 and “1
1”. Next, in step Sn<Y, the data of the 9B registration is subtracted by 1 and becomes "7". Next, the key memory 140
It is determined whether the data "6" at address 7 is function data or not, and the process returns to step S9. ``Hereafter, step S continues until the data set in the B register is ``4'' and the function data ``+'' at address 4 of the key memory 14 is read. After the processing of ~SSS is repeated three more times, the process advances to step S34, and data "4" is set in the C register. Next, the process proceeds to step s27, where the B register is cleared, and step S.

Proceed to. Next step 5lllll S21 + S
ur Stt Ss+Srs + See + SIT
, the data "123+J" is read from addresses 1 to 4 of the key memory 14 while the B register is +1 by the processing already described in Shop p-., and when the B register is "4" and the function data r+J is read, step S, to step S4, SO, Se. .

The process proceeds to step StS via 811 + SI2, and then proceeds to step 814, where the result data l'-12 is displayed on the first display section 3A of the display section 3, as shown in FIG. 5(2).
3j is displayed, and the first term "12" is displayed on the second display section 3B.
3+J is displayed.

Next, use the numeric keys and function keys to enter the second term [
When 543+J is input, the above formula [543+J is inserted into addresses 4 to 8 of the key memory 14 according to the same operation as described above. As shown in FIG. 5(3), the display section 3 displays the result data "666" on the first display section 3A, and the formula "123+543+j" on the second display section 3B. When the same content of the key memory 14 is [12
35,543+789=J, and the contents of the A register and B register are "12" and "8", respectively.

Next, press the reproduction key 4Ak to continue the calculation, and the 4th
Processing similar to that described in Figure (8) is executed,
As a result, as shown in FIG. 5(4), the first display section 3A displays the fruit data "1455J," and the second display section 3B displays 2r+543+789=j.

Next, a second embodiment will be described with reference to FIGS. 6 and 7. In this second embodiment, it is possible to display only the set number data on the second display section 3B and not display the function data when reproducing the calculation formula by specifying the mode. In this case, add the mode switch 51C setting reproduction mode "REPLAY[J" and add step Ss to the 70-chart in FIG.
s + Sss +S, the process of 7 may be added. That is, the mode switch 5 is set in advance to the position rREPLAYI[J, and the state shown in FIG. 4 (5), that is, the equation (1
), and when the contents of the A register and B register are both "12", if you operate the reproduction key 4A,
Step S + y Str Ses + S described above
Data "1" is read from address 1 of the key memory 14 through the processes of e, +820 + S21 +822. and step S2 r S3p Sei + S
By each process of ea r 5I91S21 r stz, data "l" is set in the X register, and data "2" is read from address 2 of the key memory '14. Thereafter, by repeating the same operation, the B register becomes "4" and the function data r+ is started from address 4 of the key memory 14.
'' is read out, result data ``123'' is obtained through the arithmetic processing at step S, and is stored in the X register. And step S. , Sl, and step S35 (
6), the reproduction mode is determined, and then step S3. Proceed to l and enter position reproduction mode rREPLA.
It is determined whether y n J. In this case, since the mode switch droplet 5 is in the position rREPLAY If J, it is determined that the mode is the numeric reproduction mode, and the process advances to step S3□.In this step S31, the display register A blanking code (BL) is set to D, and the number data [123J of the
As shown in Figure (1), nothing is displayed on the first display section 3A, and the function data "
The calculation formula for only the number data [123J] without the "+" will not be displayed. Note that if the determination in step S36 is "NO", the process proceeds to step S13, and the same processing as in the first embodiment is performed.

Then, a display as shown in FIG. 4 (6) is made. That is,
In this case, the mode switch 5 would have been set to the rREPLAYJ position.

Next, when the reproduction key 4A is operated one more time, the same operation as described above is executed, and only the set number data is displayed as shown in FIG. 7 (2). When the reproduction key 4A is operated one more time, As shown in FIG. 7(3), only the set number data is displayed.On the other hand, when the reproduction key 4B is operated, only the set number data of the above calculation formula is sequentially reproduced from the reverse direction.

In each of the above embodiments, the present invention is applied to a small electronic calculator equipped with a verification function, but even in a calculator without a verification function, the first display section and the second display section The calculation result may be displayed on the first display section, and the calculation formula to be input may be continuously displayed on the second display section. Further, in each of the above embodiments, the first display section is configured with 8 digits of Japanese character display segments,
In addition, although the second display section is made up of a 3×5 dot matrix display with 9 digits, the present invention is not limited to this, and both display sections may be made up of either Japanese character display segments or dot matrix displays. Of course, the number of digits is also arbitrary.

Further, although in the second embodiment, no information is displayed on the first display section 3A in the 1.numerical number reproduction mode, the calculation result of the first display section 3AK may be displayed.

As explained above, this invention is provided with two display sections, one display section continuously displays the calculation formula entered manually, and the other display section displays the display data of the one display section. Since we have provided a small electronic calculator that simultaneously displays calculation result data corresponding to , there is an advantage that the relationship between the input calculation formula and its calculation result data can be checked at all times, and key operation mistakes can be prevented.

In addition, the present invention stores the calculation formula entered manually and is provided with two display sections, one of which displays the numeric data and function data in the above calculation formula in sequence, and the other display section. The display section displays calculation result data corresponding to the display data on the one display section, and the calculation formula is read out by a predetermined key operation and displayed continuously on the one display section. Since we provide an electronic calculator, we can always check the correspondence between calculation formulas and their calculation results during manual keystrokes or calculations, which has the advantage of preventing key operation errors. Furthermore, since a plurality of pairs of numerical data and function data can be displayed simultaneously in a calculation formula, there is an advantage that the context of the formula can be confirmed even more clearly. Furthermore, if the calculation formula can be reproduced from either the head direction or the reverse direction, there is an advantage that the calculation can be performed more easily. It also has the advantage that it is easy to delete or insert a part of the calculation formula being reproduced, and calculations can be made faster.

[Brief explanation of drawings]

1 to 5 show a first embodiment in which the present invention is applied to a small electronic calculator equipped with a verification function, FIG. 1 is a plan view of the computer, FIG. 2 is a circuit configuration diagram, and FIG. The figure is a flowchart to explain the overall operation, Figure 4 is a diagram showing the key operations and display states when inputting and reproducing a calculation formula, and Figure 5 is a diagram showing a part of the calculation formula when reproducing it. 6 and 7 show the second embodiment, and FIG. 6 is a flowchart of the main part for explaining the operation, FIG. 7 is a diagram showing key operations and display states during reproduction. 2-°・Key human power section, 3...Display section, 3A...1st
Display unit, 3B...Second display unit, 4A, 4B...Reproduction key, 5...Mode switch, 11...Control unit, 1
2... Memory input control section, 13... Arithmetic section, 14.
- Key memory, 15...- Arithmetic register, 16...
Memory output control unit, 17A...first display control unit, 17
B...Second display control unit O Patent applicant Casio Computer Co., Ltd. Representative Patent Attorney Yama 1) Hatahiko -'-゛, :, / Figure 3 CB) Figure 3 (C) Figure 4 336 - Figure 5 Figure 6 Figure 7 Le 337

Claims (2)

[Claims] (1) Output by key manual means having numeric keys for inputting numerical data and function keys for giving calculation instructions such as four arithmetic operations, and key operations based on a desired calculation formula on the key manual means. a storage means for sequentially storing numeric data and function data stored in the memory; a display means, a calculation means for performing calculations based on the numeric data and function data stored in the storage means corresponding to the calculation formula displayed on the first display means; A small electronic calculator characterized by comprising a second display means for displaying calculation results. (2) The key manual means has keys for sequentially reading out the numeric data and function data stored in the storage means in the order in which they were written first or in the order in which they were newly written, and each time the key is operated. The calculation formulas corresponding to the numerical data and function data sequentially read out are displayed on the first display means, and the calculation formulas displayed on the first display means are displayed on the second display means. A small electronic calculator according to claim 1, characterized in that a corresponding calculation result is displayed.