How to store a result in a variable and reuse it

The screen uses lowercase $a$, even though the key is marked A. After $a\times 5$, Ans holds $120$ while $a$ still holds $24$. After the division, Ans becomes $5$ and $a$ remains $24$. The letter keeps the value until you replace or clear it.

To inspect or edit it, follow check and change a stored variable.

Memory M is the variable $m$ on the screen. M+ and M− treat an empty $m$ as $0$, so start with nothing stored in it; AC and reloading the page do not clear it, so to empty it first follow check and change a stored variable. The example adds two shop bills, then takes off a refund.

Adding a displayed answer to M or subtracting it from M leaves Ans unchanged. The arrow result shows the new total in $m$.

1. Enter $12\times 5$ and press . The first bill is $60$.
2. Press to add the displayed answer to M. The screen shows $60\to m$.
3. Enter $8\times 7$ and press to get $56$. Press to add it to M. The screen shows $116\to m$.
4. Press to recall M. The line and preview show $m$; press to see $116$.
5. Enter $16$ and press . Press to subtract the refund from M. The screen shows $100\to m$. Press , then , to read back $100$.

• The preview still contains a letter: $5\times a$ is expected before you press the equals key. If you calculate with a letter you have never stored, the answer keeps that letter too; an unset letter is not zero. Store the value in the letter you intend to use.
• You stored in the wrong letter: store the value again in the correct one. The first letter keeps its value. Storing again in the same letter replaces its value without asking.
• Storing did nothing: after STO, press the letter's own key, without ALPHA. A blank line stores nothing; calculate the result first, then repeat the storing step (step 2 under Store the area and use it again).