How does the tape work?

Every calculation you complete stays on the tape as a visible line showing the full expression and result. Tap any result to start a new calculation that references it. The tape scrolls so you can review your full working history.

How do I edit a calculation?

Tap any number or operator on the tape to edit it in place. The value highlights and you can type a new one. All calculations that depend on that line update automatically. Tap cancel to revert your edit.

How do I reuse a result?

Tap any result on the tape to start a new calculation using that value. The new line will reference the original — if you change the original, the dependent calculation updates too.

How do decimal places work?

Open Settings and adjust the decimal places slider (0–10). All results on the tape update immediately to reflect the new precision. The full value is always preserved internally.

What's the difference between wrap and scroll mode?

Wrap mode shows long expressions across multiple lines so you can see everything at once. Scroll mode keeps each calculation on one line and lets you swipe horizontally to see the full expression.

How do I copy a result?

Long-press the main display to copy the current result to your clipboard. You can also tap the tape to copy individual line results.

How does the clear button work?

Clear steps through three levels: first it clears the current input, then removes the current line, then clears the entire tape. This lets you undo progressively without losing everything at once.

Does Sumthing use the internet?

No. Sumthing has no network features, no accounts, no tracking, and no analytics. Everything stays on your device.