Editing Calculator (section)

===Key layout===
The following keys are common to most pocket calculators.  While the arrangement of the digits is standard, the positions of other keys vary from model to model; the illustration is an example.
{| class="wikitable" style="clear:right"
|+ Calculator buttons and their meanings
|-
| MC or CM || '''M'''emory '''C'''lear
| rowspan="15" |{{Calculator layout|float=center}}
|-
| MR, RM, or MRC || '''M'''emory '''R'''ecall
|-
| M− || '''M'''emory '''Subtraction'''
|-
| M+ || '''M'''emory '''Addition'''
|-
| C or AC || '''A'''ll '''C'''lear
|-
| CE || '''C'''lear (last) '''E'''ntry; sometimes called CE/C: a first press clears the last entry (CE), a second press clears all (C)
|-
| ± or CHS || Toggle positive/negative number aka '''CH'''ange '''S'''ign
|-
| % || [[Percent]]
|-
| ÷ || [[Division (mathematics)|Division]]
|-
| × || [[Multiplication]]
|-
| − || [[Subtraction]]
|-
| + || [[Addition]]
|-
| . || [[Decimal point]]
|-
| √ || [[Square root]]
|-
| = || Result
|}

The arrangement of digits on calculator and other [[numeric keypad]]s with the {{key press|7}}-{{key press|8}}-{{key press|9}} keys two rows above the {{key press|1}}-{{key press|2}}-{{key press|3}} keys is  derived from calculators and [[cash register]]s. It is notably different from the layout of [[Telephone keypad|telephone Touch-Tone keypads]] which have the {{key press|1}}-{{key press|2}}-{{key press|3}} keys on top and {{key press|7}}-{{key press|8}}-{{key press|9}} keys on the third row.