JPH0122658B2 - - Google Patents

Description

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

Conventionally, small electronic calculators have been developed that have a verification function that can store entered calculation formulas and read out the calculation formulas by pressing a specified key.
It has been put into practical use. In this type of calculator, for example, when you enter the formula "123+456+789=", during verification, the stored number data and function data in the formula are stored in pairs ("123
+", "456+", etc.) and displayed on the display section, and then the final calculation result data "1368" is finally displayed on the display section. In this way, with conventional calculators, 1
Since only one pair of numeric data and one function data is displayed on one display section, intermediate results of calculations cannot be reproduced at the same time as input data, which is inconvenient. Furthermore, since the method is displayed in pairs, the relationship between the preceding and succeeding terms in the calculation formula and the term currently being displayed is unclear.
Furthermore, the function data has the disadvantage that the function display is difficult to understand because the function data is additionally displayed in a partial area of the Japanese character-shaped multi-digit display section.

On the other hand, even in small electronic calculators that do not have the above-mentioned verification function, a series of numeric data and function data in a calculation formula entered at the time of key input, as well as intermediate and final results of the calculation, can be displayed simultaneously on the display. There was no display, and it was difficult to see the relationship between the input calculation formula and its calculation result, which was inconvenient in some cases.

This invention was made against the background of the above-mentioned circumstances, and its purpose is to provide two display sections, one display section to continuously display the key-input calculation formula, and the other display section to continuously display the key-input calculation formula. 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 input section 2 and a display section 3 are provided on the top side of a case body 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, batteries, etc. that make up the system are housed there. The key input section 2 includes band number keys from □0 to □9, various function keys for four arithmetic operations such as □+, □-, □×, □÷, and other operations.
Reproduction keys 4A, 4B, a mode switch 5, and a contrast (CNT) key 6 are provided, respectively.
The reproduction keys 4A and 4B each read out calculation formulas entered using the numeric keys, function keys, etc. from a key memory (described later) that stores them in the order of input, and display them on the display unit 3 at the time of verification. This is the key to reproducing it. In this case, 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 formula from the end of the formula to the beginning (reverse direction). ) Give instructions for sequential reproduction.

Mode switch 5 is in the "OFF" position for off mode, and in the "REPLAY" position for reproduction mode.
"DISP ₁ " is a mode that always displays the contents of the independent memory of the second display section (described later) at the "MEMORY" position.
A mode for displaying only the first display section, which will be described later, is set respectively at the position. The contrast key 6 is a key for adjusting the display brightness (contrast) of the display section 3 made 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 drive voltage, the contrast key 6
Also provided is a counter whose contents go up/down by operating the reproduction keys 4A, 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. The first display section 3A has an 8-digit configuration using Japanese character-shaped display segments, and the second display section 3B has a 9-digit configuration using a 3.times.5 dot matrix display.
In addition, as shown in the left end of the first display section 3A and the second display section 3B, display elements such as ×, ÷, +, -, K, RP, M, etc. are also provided, and each function of addition, subtraction, multiplication, division, and constant is provided. display, reproduction mode display, and memory mode display.

Next, the circuit configuration will be explained with reference to FIG. The output of each key and switch of the key input section 2 is controlled by the control section 1.
Enter 1. This control section 11 is a circuit that controls various operations of this small electronic calculator, and is composed of, for example, a microprocessor. Then, control instructions O ₁ to _{O 5} are output. Memory input control section 1
2 receives data corresponding to the output of the key input section 2 from the control section 11, as well as calculation result data from the calculation section 13. Then, the memory input control unit 12 transfers the input data to the key memory 14 or the operation register 1 according to the control instruction _O2 .
Enter 5. The key memory 14 stores calculation formulas input by key operations, and its storage capacity is equivalent to 50 key operations (number of numeric keys and function keys). The operation register 15 includes an X register, a Y register, which stores the number of operations, an operand, an A register, which counts the number of key operations mentioned above, and the address of the key memory 14 where the data of the least significant digit of the second display section 3B is stored. It consists of a B register indicating which data is stored in the memory, C, D, and N registers for temporary storage, other registers (not shown), and an independent memory. Also,
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 outputs the above input data to the calculation section ₁₃ and the first
It is output to either the display control section 17A or the second display control section 17B.

The calculation unit 13 executes various calculations in accordance with the control instruction O ₁ and outputs the calculation result data to the memory input control unit 12 as well as outputs the result data J of the jersey calculation to the control unit 11 .

First display control section 17A, second display control section 17B
have display registers D ₁ and D ₂ , respectively, and control the display operations of the first display section 3A and the second display section 3B according to control instructions O ₄ and O ₅ , respectively.

Next, the operation of the above embodiment will be explained with reference to the flowcharts shown in FIGS. 3A, B, and C. Now, use the small electronic calculator of the present invention to input the following formula (1) and perform calculations, and after inputting the formula, display the above formula on the display 3 for verification.
Let's discuss the case where the image is reproduced.

123+456+789=1368 (1) First, set mode switch 5 to "REPLAY" to enter reproduction mode. Next, operate the number key □1 to input the numerical value "123". Therefore,
The output of the key input section 2 shown in FIG. 2 is input to the control section 11, and the control section 11 determines the type of operation key and outputs control commands _O1 to _O5 with corresponding contents.
That is, in this case, the determined number data "1"
is input to the X register of the calculation register 15 under the control of the memory input control section 12. The data "1" in this 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 the data "1" in the X register is transferred to the display register D1 of the first display control section 17A.
displayed in the digit.

_The above operation will be explained with reference to the flowchart _of FIG. The keys are reproduction keys, calculation keys (number keys, □+, □-,
□×, □÷, □= function key) or □
C
(Clear) Performs processing to determine whether it is a key. Since the current key is a numeric key, the process goes 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 advances to step _S15 and the numeric data is "1".
is input to the X register. Next, in step _S16 , it is determined whether the reproduction key 4A or 4B has been operated, that is, whether the calculation formula is being reproduced.
Since it is not currently being reproduced, the process proceeds to step _S17 , and it is determined whether or not the □C key has been operated while the calculation formula is being reproduced, thereby deleting part of the data, that is, whether or not it is being deleted. In this case, the deletion is not in progress, so the step
Proceeding to _S13 , the data "1" in the X register is transferred to the display register _D1 , and the data in the key memory is transferred to the display register _D2 . Then step
The numerical value "1" is displayed on the first display section 3 by the display processing of _S14 .
A, but since no data has been input to the key memory yet, nothing is displayed on the second display section 3B. Next, the key sampling process of step _S1 is executed again.

Similarly, when the number 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 unit 3 at the time when the above key operations are completed.

Next, when the □+ key is operated, the data "123" in the X register is transferred to the Y register, and the data "123+" is set in the key memory 14. Then, this data “123+” is transmitted to the second display control unit 17.
B's display register D ₂ and the second display section 3
It is displayed on B. Also, the first calculation process is executed in the calculation unit 13, and the calculation result data is "123".
is displayed on the first display section 3A.

That is, the above operation will be explained with reference to the flowchart of FIG. 3. After each process of steps _S1 and _S2 , it is determined in step _S3 that the operation key is a function key. Therefore, the process advances to step _S4 , where it is determined whether or not it is being reproduced, as in step _S16 , and since the answer is "NO", the process advances to step _S5 , where it is determined whether or not it is being deleted, as in step _S17 .
Since the answer is "NO", proceed to the next step _S6 .
In step _S6 , data "123+" is input into the first to fourth digits of the key memory 14 in accordance with the contents of the B register (currently "0"). Next step
The number of data "4" is counted by _S7 and set in the A register. Next, in step _S3 , the number of data "4" is set in the B 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 _S9 , the data in both the X and Y registers are added, and then in step _S10 , 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, since the answer is "NO", the process proceeds to step _S11 , where the same process as step _S5 is executed, each process of steps _S13 and _S14 is further executed, and the process returns to step _S1 . FIG. 42 shows the display state at this point.

Next, when the data "456" is input using the numeric key, the processing of each step is executed in the same manner as in the case of FIG. 4, described above. FIG. 4 shows the display state. Next, when the □+ key is operated, data "456+" is further input into the key memory 14, and its contents become "123+456+". Also, step
Through the processing of S ₇ and S ₈ , both the data in the A register and the B register become "8". and data "123"
The addition of "456" to "456" is executed, and the display state of the display unit 3 becomes as shown in FIG.

Next, input the data "789" and then operate the □= key, and the key memory 14 will have the data "789"
=" is input, and both the A register and the B register are incremented by 4 to become "12", and the operation result data "1368" is calculated. The display state of the display unit 3 becomes as shown in FIG. 4 and 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 processing in step _S2 following step _S1 that the reproduction key 4A has been operated, and the process proceeds to step _S18 , where it is determined that it is the reproduction key 4A in the forward direction. Next step
The process proceeds to _{step S19} , and it is determined whether the contents of both the A and B registers match. Since they are both "12", the process proceeds to the next step _S20 , and the B register is cleared. Then proceed to step S ₂₁ and B
The register is incremented by 1 and becomes "1". The program 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 program returns to step _S2 .

In step _S2 , it is determined whether the data "1" just read from the key memory 14 corresponds to the □C key, the calculation key, or the reproduction key, and the process then proceeds to step _S3 . Then, in step _S3 , it is further determined whether the key is a numeric key or a function key. Since this is the numeric key, the next step is
Proceeding to _S15 , data "1" is input to the X register. Next, the process advances to step _S16 , where it is determined whether or not it is being reproduced.
Proceed to S ₁₉ . Since the contents of the A and B registers do not match, the process advances to step _S21 , where the B register is incremented by 1 and becomes "2". and step
The next data "2" is read from address 2 of the key memory 14 by _S22 .

Steps S ₂ , S ₃ , S ₁₅ , S ₁₆ , S ₁₉ , and S ₂₁ are executed for the data “2” as well as for the data “1”, and during this time, the contents of the X register become “12”.
Also, the B register becomes “3” and the next step is started.
Data "3" is read from the key memory 14 by _S22 . Then, steps S ₂ , S ₃ , S ₁₅ , S ₁₆ , S ₁₉ , and S ₂₁ are executed for this data “3”, and the contents of the X register become “123” and the B
The register becomes "4". Therefore, the function data "+" is read from address 4 of the key memory 14 in the next step _S22 . Therefore, after step _S2 , it is determined in step _S3 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 _S9 , where result data "123" is obtained through the calculation process. Next, after processing steps S ₁₀ and S ₁₁ , the process proceeds to steps S ₁₃ and S ₁₄ , and the result data "123" is displayed on the first display section 3A of the display section 3, as shown in FIG. The calculation formula "123+" is also displayed on the second display section 3B, and the key input can be confirmed.

Next, when you operate the reproduction key 4A for the second time, 1
The processing of each step is executed in the same way as the first time, and when the function data "+" is read out, the display section 3 shows a display as shown in FIG. The second calculation result data "579" is displayed, and the calculation formula "123+456+" is displayed on the second display section 3B. Also, during this time, the contents of the B register increase to "8".

The same thing happens when the reproduction key 4A is operated for the third time.
When the function data "=" is read out, the display section 3 enters a display state as shown in FIG. 4. In this case, since the second display section 3B can only display up to 9 digits, the upper 3 digits of the formula "123" are not displayed. Also, during this time, the contents of the B register increase to "12".

As described above, by operating the reproduction key 4A three times in this case, it is possible to perform the verification calculation 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, the reproduction key 4B is first operated once. At this time, after processing steps S ₁ and S ₂ ,
It is determined through the process of _S18 that the reproduction key 4B has been operated, and the process advances to step _S23 of the flowchart of FIG. 3B. In step _S23 , it is determined whether the content of the B register is "1" or not, and since it is currently "12", the process advances to step _S24 , and the B register is set to -1.
and becomes "11". The process then proceeds to step _S25 , where it is determined whether the data at address 11 of the key memory 14 is function data. Since the data at address 11 is now "9", the result is "NO" and the process returns to step _S23 . Then, in step _S23 , the contents of the B register are decremented by 1 until the function data "+" at address 8 of the key memory 14 is detected.
_S24 and _S25 are repeated three more times, and when function data "+" is detected by the processing in step _S25 , the process advances to step _S26 , and data "8" in the B register is transferred to the C register. protected.
Next, the process proceeds to step _S27 , where the B register is cleared, and the process proceeds to step _S19 . In step S ₁₉ , the A register is currently ``12'', so ``NO'' is selected.
Proceeds to step S ₂₁ and B register becomes +1
Then, in step _S22 , the data "1" at address 1 of the key memory 14 is read out, and then the process advances to step _S2 .

Hereinafter, _similar operations will be performed in _the above-mentioned calculation _of FIG _.
The data "2" at address 2 of the key memory 14 is read by each process of S ₁₉ , S ₂₁ and S ₂₂ , and then the data "3" of address 3 of the key memory 14 is read by the process of the same step. Similarly, when the data "+" at address 4 is read out by the processing in step _S3 , the process proceeds to step _S4 , and after the arithmetic processing in step _S9 , the process proceeds to step _S10 . In this step _S10 , it is determined that reverse reproduction is being performed, and the process proceeds to step _S12 , where it is determined whether the data "4" in the B register and the data "8" in the C register match. Now it's "NO" so take steps
Proceed to S ₁₉ . Then, in the same manner, until the data in the B register reaches "8" and matches the contents of the C register, the B register is +1 and the data "4" at addresses "5" to "8" in the key memory 14 is changed.
An operation of sequentially reading and determining "5", "6", and "+" is executed. After reading the function data "+", if it is determined in step _S12 that the registers B and C match, the process proceeds to step _S13 , and further, the process in step _S14 causes the display section 3 to display the first register. The result data "579" is displayed on the first display section 3A, and the calculation formula "123+456+" is displayed on the second display section 3B, as shown in FIG. 4, respectively.

Furthermore, when the reproduction key 4B is operated once more, steps S ₁ , S ₂ , S ₁₈ , S ₂₃ , S ₂₄ , and S ₂₅ are performed in the same manner as described above.
After each process, steps _S23 , _S24 , and _S25 are repeated while decrementing the B register by 1 until the function data "+" at address 4 of the key memory 14 is read out, and then the function data "+" is read out. When it is determined in step _S25 that "+" has been read out, the process advances to step _S26 , where data "4" is set in the C register. Then, the B register is cleared in step _S27 , and the steps _S19 , _S21 ,
By repeating S ₂₂ , S ₂ , S ₃ , S ₁₅ , S ₁₆ , S ₁₉ , etc., the B register becomes "4" and the function data "+" is read, then steps S ₃ and S ₄ through steps S ₉ , S ₁₀ , S ₁₂ , S ₁₃ and S ₁₄ , result data “123” is displayed on the first display section 3A of the display section 3 as shown in FIG. Further, the calculation formula "123+" is displayed on the second display section 3B.

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, in FIG. 5 1
As shown in the figure, the calculation formula "123+456" is displayed on the second display section 3B.
When "+" is displayed, the second term "456+" is deleted and the expression "543+" is inserted in its place.
Note that the contents of the A register and B register are now "12" and "8", respectively.

When the □C key is operated in _the state shown _{in FIG} .
The data "+" at address 8 of the key memory 14 is cleared. Next, in step _S30 , the key memory 14 is
The data within is shifted to the right by one digit, and the cleared data area is filled in. Next, in step _S31 , the A register is incremented by 1 to become "11". Next, in step _S32 , the data in the B register is decremented by 1, and
It becomes "7". Next, it is determined whether the data "6" at address 7 of the key memory 14 is function data or not, and the process returns to step _S29 .

Thereafter, the processing of steps _S29 to _S33 is repeated three more times until the data in the B register becomes "4" and the function data "+" at address 4 of the key memory 14 is read out, and then step _S34 is performed. Proceed to
Data "4" is set in the C register. Next, proceed to step _S27 , the B register is cleared,
Proceed to step _S19 . Next steps S ₁₉ , S ₂₁ ,
The data "123+" is read from addresses 1 to 4 of the key memory 14 while the B register is incremented by 1 through the already described processing of S ₂₂ , S ₂ , S ₃ , S ₁₅ , S ₁₆ , S _{17 ,} S 19 , etc. When the function data "+" is read out when the B register is "4", the process starts from step _S3 through steps _S4 , _S9 , _S10 , _S11 , and _S12 .
The process proceeds to step _S13 , and then proceeds to step _S14 , where the result data "123" is displayed on the first display section 3A of the display section 3, and the result data "123" is displayed on the second display section 3B, as shown in FIG. The first term “123+” is displayed.

Next, when the second term "543+" is input by operating the numeric keys and function keys, the above expression "543+" is inserted into addresses 4 to 8 of the key memory 14 in the same manner as described above. As shown in FIG. 5, on the display section 3, the result data "666" is displayed on the first display section 3A, and the result data "666" is displayed on the second display section 3B.
The expression "123+543+" is displayed. At this time,
The contents of the key memory 14 are "123+543+789=", and the contents of the A register and B register are "12" and "8", respectively.

Next, when the reproduction key 4A is operated to continue the verification, the same process as described in FIG. 4 is executed, and as a result, as shown in FIG. Result data “1455” in 3A
is displayed, and the formula "+543" is displayed on the second display section 3B.
+789=" is displayed.

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 numerical 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 numeric reproduction mode "REPLAY" to the mode switch 5, and as shown in Figure 6,
In the flowchart of FIG. 3A, steps S ₃₅ , S ₃₆ ,
Just add the processing of S ₃₇ . That is, set the mode switch 5 to the "REPLAY" position in advance,
The state shown in Figure 4, 5, that is, the input of formula (1) is complete, and the contents of both the A register and B register are "12".
If the reproduction key 4A is operated at this time, the data "1" is retrieved from address 1 of the key memory 14 through the processes of steps S ₁ , S ₂ , S ₁₈ , S ₁₉ , S ₂₀ , S ₂₁ and S ₂₂ described above. is read out. and steps S ₂ , S ₃ ,
Data "1" is set in the X register by each process of S ₁₅ , S ₁₆ , S ₁₉ , S ₂₁ and S ₂₂ and data "2" is read from address 2 of the key memory 14. Thereafter, by repeating the same operation, when the B register becomes "4" and the function data "+" is read from address 4 of the key memory 14, the process proceeds to step _S9.
The result data "123" is obtained by the calculation process, and
stored in a register. and steps S ₁₀ and S ₁₁
The process then proceeds to step S ₃₅ (FIG. 6), where the reproduction mode is determined, and then proceeds to step S ₃₆ , where it is determined whether the numeric reproduction mode is "REPLAY". In this case, since the mode switch 5 is in the "REPLAY" position, it is determined that the mode is the numeric reproduction mode, the result is "YES", and the process proceeds to step _S37 . In this step _S37 , the blanking code B _L is set in the display register _D1 , and the number data "123" of the Y register is transferred to the display register _D2 . Next, through the display processing in step _S14 , the seventh
As shown in FIG. 1, nothing is displayed on the first display section 3A, and a calculation formula containing only the numeric data "123" without the function data "+" is displayed on the second display section 3B. will be done. Note that the above steps
If "NO" is determined in _S36 , the process advances to step _S13 , and the same processing as in the first embodiment is performed. Then, a display as shown in FIG. 4 and 6 is made.
That is, in this case, the mode switch 5 was set to the "REPLAY" 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. 72. Furthermore, when the reproduction key 4A is operated once, only the set number data is displayed as shown in FIG. 7. 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 a calculator without a verification function can display the first display section and the second display section as in the present invention. 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,
Furthermore, although the second display section is made up of a 3 x 5 dot matrix display with 9 digits, the present invention is not limited thereto, and both display sections may be made up of either a Japanese character display segment or a dot matrix display. Of course, the number of digits is also arbitrary. Further, in the second embodiment, nothing is displayed on the first display section 3A in the numerical reproduction mode, but the calculation result may be displayed on the first display section 3A.

As explained above, this invention is provided with two display sections, one display section continuously displays the calculation formula entered by key, and the other display section displays the display data of the one display section. The calculation result data corresponding to the above calculation formulas are displayed simultaneously, and the calculation formula entered by the key is memorized, and when data is read out, the numeric data and function data of the above calculation formula are displayed on one display section. The display is displayed in sequence, and the calculation result data corresponding to the data displayed on one display is displayed on the other display, so that calculation formulas and their calculations can be viewed during key input or verification. This has the advantage that you can always check the correspondence with the results and prevent key operation mistakes. Furthermore, since a plurality of pairs of numeric 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 in either the forward or reverse direction during verification, there is the advantage that verification can be performed more easily. Furthermore, it is easy to delete or insert a part of the calculation formula being reproduced, which has the advantage that 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 diagram, and FIG. The figure is a flowchart to explain the overall operation, Figure 4 is a diagram showing the key operation and display states when inputting and reproducing a calculation formula, and Figure 5 is a part of the calculation formula when reproducing it. Figures 6 and 7 show the second embodiment, and Figure 6 is a flowchart of the main part to explain the operation. FIG. 7 is a diagram showing key operations and display states during reproduction. 2...Key input section, 3...Display section, 3A...First display section, 3B...Second display section, 4A, 4B...
Reproduction key, 5...Mode switch, 11...Control unit, 12...Memory input control unit, 13...Arithmetic unit, 14...Key memory, 15...Arithmetic register, 16...Memory output control unit, 17A ...First
Display control section, 17B...Second display control section.

Claims (1)

[Scope of Claims] 1. A key input means having a numeric key and a function key; a first display means for cumulatively displaying data input from the key input means for each key input; a storage means for sequentially storing input data; a reading means for reading out the corresponding numeric data and function data one by one from the storage means and cumulatively displaying them on the first display means; and the above-mentioned key input. a calculation means that executes calculations according to key operations, and performs calculations according to the data each time the data is read by the reading means; and a second calculation means that displays the calculation results of the calculation means. display means, and is characterized in that, as the mathematical formula displayed on the first display means changes, the calculation result displayed on the second display means changes to a value corresponding to the mathematical formula being displayed. A small electronic calculator.