Tape Calculator with Notes

A calculator that doesn't erase what came before. Every entry leaves its own line, with a note beside it, and you can fix any number from half an hour ago: the whole tape recalculates itself. It's the paper adding machine's model, not the pocket calculator's. Lines apply in order, top to bottom: 2 + 3 × 4 is 20. THE TAPE • A note on every line, and text notes that separate blocks without entering the calculation. • Subtotals with "=", named results you can reuse further down, and lines you can leave out of the calculation without deleting them. • Percentages with calculator semantics: "+ 18 %" adds 18 % of the running total and shows the resolved amount beside it. • Exact decimal arithmetic throughout: 0.1 + 0.2 is exactly 0.3. INPUT • Two typing orders: sign first, like a calculator, or sign last, like an adding machine. • Its own keypad with memory (M+ M− MC MR), a configurable tax…