How to use the adding machine
- Add: type an amount and press Enter or +. Subtract: press −.
- Subtotal ◇ prints the running total on the tape and keeps going. Total ✱ prints the total and starts a new count.
- + Tax adds sales tax at your rate on everything so far.
- Fix a mistake: remove any line with its × and the total updates.
- Print tape prints only the tape, like a receipt. Copy tape copies it as text for an email or spreadsheet.
You can type a small sum as one entry, like 3 × 4.25 for three items at $4.25. Your tape is saved in this browser, so it's still there if you come back. Nothing is sent anywhere.
Why an adding machine?
Bookkeepers, cashiers and anyone checking receipts use adding machines because the tape is a record: you can see every number that went into the total and spot a typo, which a regular calculator can't show you.