Parts of a Calculator – Keys, Display and Solar Cell

All 12 parts on the diagram

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The main parts 5

Display Shows the numbers you enter and the result.
Number keys Ten keys, 0 to 9, for entering a number digit by digit.
Operation keys Divide, multiply, subtract and add.
Equals key Finishes the calculation and shows the result.
Decimal point key Puts the decimal point into the number being entered.

The other keys and the power 7

On/clear key (ON/C) Turns the calculator on and clears the whole calculation.
Clear entry key (CE) Clears only the last number entered, not the whole calculation.
Memory keys Add to, subtract from and recall one stored number.
Square root key Gives the square root of the number showing.
Percent key Works out percentages.
Change sign key (+/−) Switches the number showing between positive and negative.
Solar cell Turns light into the power that runs the calculator.

How this list was compiled: Every name checked on 2026-09-30 in two independent places, an encyclopedia and makers’ own manuals. (1) Wikipedia, Calculator, https://en.wikipedia.org/wiki/Calculator (a keypad with buttons for digits and arithmetical operations; the display panel; solar cells or batteries as the power source; the table of buttons and their meanings: MC, MR or MRC, M− and M+ for memory, C or AC for all clear, CE for clear last entry, ± for change sign, %, the four operations, the decimal point, the square root and = for the result). (2) A calculator maker's guide for a school scientific model (1997), https://archive.org/details/manualsonline-id-7694cf74-0334-4ebb-8f1e-f901f463cab4 (ON/C turns the calculator on and clears it; CE/C clears the value just entered; the solar panel; the display; memory; the key that changes the sign of the value just entered; the equals key completes all pending operations; percent; square root). (3) A second maker's operation manual for a desk calculator, https://archive.org/details/manualsbase-id-25325 (key operations and display; clearing the memory; the built-in solar cell; the decimal point). Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry. Own original design; no maker’s model, name or mark is shown. Licence: own work

How it works

The parts of a calculator are its display, its keys and its power source. This one has number keys, four operation keys, an equals key, memory keys, two clear keys and a solar cell.

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The keys you use most

Number keys and the decimal point key enter a number. An operation key says what to do with it, and the equals key shows the result in the display.

Clearing and remembering

The clear entry key, CE, wipes only the number you just typed; the on/clear key wipes everything. The calculator can also hold one number in memory: M+ adds the number showing to it, M− subtracts it, and MRC brings it back.

Keys sit in different places on different calculators. Go by the sign on the key, not by where it is.

Questions and answers

What are the main parts of a calculator?

The display, which shows numbers and results; the keypad, with number keys, operation keys and an equals key; and the power source, a solar cell or a battery.

What is the difference between C and CE on a calculator?

CE means clear entry: it removes only the last number entered. C, or AC for all clear, removes the whole calculation.

What do M+, M− and MRC mean?

They are memory keys. M+ adds the number in the display to the stored number, M− subtracts it, and MRC recalls the stored number.

What does the +/− key do?

It changes the sign of the number in the display, from positive to negative or back.