Slate Tally

Slate Tally is a calculator that takes a whole line at a time and writes down what it worked out.

Type 1200 + 340 x 3 the way you would say it. Multiplication and division are counted before addition, brackets win over both, and a grey line under the keypad shows the running result while you are still typing — so a mistyped digit is obvious before you press equals.

Percent behaves the way people actually mean it. 200 + 10% gives 220, because the percent is taken from the number on the left. With multiplication and division it is a plain share: 200 x 10% gives 20.

Every finished line lands in the tape with its result and the time, newest on top. Tap any line there and it goes back into the keypad, ready to be changed and counted again. The tape also totals the results, which is what turns a pile of separate sums into one number at the end of the day. Lines can be removed one by one or wiped all at once, and the tape can be switched off entirely if you would rather nothing was kept.

There is a memory for the number you need to hold on to: M+ and M- move the current line in and out of it, MR types the stored value back, MC clears it. What memory holds is always visible above the keypad, so nothing is stored blind.

The setup is short on purpose: decimals fixed at zero, two or four places or as many as the result needs, thousands spaced out or not, a short buzz under each key or silence.

Everything stays on the phone. No accounts, no sign-in, no network calls, no ads and nothing to buy.

Features:
- The whole line at once, with brackets and the right order of operations
- A running result shown while you type
- Percent taken from the number on the left, as expected
- A tape of every finished line, with results and times
- Sum of all results in the tape
- Tap a line to put it back into the keypad
- Memory keys with the stored value always in sight
- Fixed or automatic decimals, spaced thousands, buzz on tap
- Works fully offline