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Short answer
M+ adds the number on screen to the memory register, M− subtracts it, MR recalls it to the screen and MC sets it back to zero. Typing 12.5 M+ then 7.5 M+ then MR shows 20.
1. The four keys
| Key | Meaning | Effect |
|---|---|---|
| MC | Memory clear | Sets memory to 0 |
| MR | Memory recall | Puts the stored number on screen |
| M+ | Memory add | Adds the screen number to memory |
| M− | Memory subtract | Subtracts the screen number from memory |
2. Example: a running subtotal
- 1Press MC. Memory is 0.
- 2Type 12.5 and press M+. Memory is 12.5.
- 3Type 7.5 and press M+. Memory is 20.
- 4Type 4 and press M−. Memory is 16.
- 5Press MR. The screen shows 16.
3. Good uses
- Adding the results of several separate calculations, such as 3 × 4 and 5 × 6.
- Forcing the multiplication-first order, as in the left to right vs PEMDAS guide.
- Keeping a total while you check other numbers.
4. Memory and AC
AC clears the current calculation but not the memory. Use MC to empty it. The MEM label on the Basic Calculator always shows the stored value.
5. History tape
The calculator also keeps your last 50 completed calculations, newest first. You can copy the list or print it to check your working.
6. Frequently asked questions
What does M+ do?expand_more
It adds the number on the screen to the memory register.
Does AC clear the memory?expand_more
No. AC clears the current calculation. Use MC to clear memory.
How do I see what is in memory?expand_more
Press MR, or read the MEM label above the display.
Is there a history of my calculations?expand_more
Yes. The history tape keeps your last 50 completed calculations.