What each key does
| Key | Name | What it does |
|---|---|---|
| AC | All clear | Clears the current calculation completely. |
| C | Clear | On many calculators the same as AC; on some it clears the last entry. |
| CE | Clear entry | Clears only the number you just typed, so you can retype it without starting over. |
| M+ | Memory plus | Adds the number on the display to the memory. |
| M− | Memory minus | Subtracts the number on the display from the memory. |
| MR | Memory recall | Shows the number stored in memory. |
| MC | Memory clear | Sets the memory back to zero. |
| MRC | Memory recall / clear | Press once to recall the memory; press twice to clear it. |
| GT | Grand total | Adds up every result you got by pressing = since the last clear. |
| % | Percent | Works out percentages; how it behaves varies by model. |
| +/− | Change sign | Makes the displayed number negative or positive. |
Using memory to add up a bill
To total 3 items at $4 and 2 at $7.50: press 3 × 4 = then M+ (memory holds 12), then 2 × 7.5 = then M+ (memory holds 27). Press MR or MRC once to see 27.
How the % key usually works
On most basic calculators, 200 × 15 % shows 30 (15% of 200), and 200 + 15 % shows 230 (200 plus 15%). Models differ, so if a result looks odd, work it out as 200 × 0.15 instead, or use the percentage calculator.
Try it
The basic calculator and the adding machine, which keeps a running tape, work right in your browser.
Every worked example on this page was checked with Calcist's own engine and an independent reference.