Sumi: Notepad Calculator

Sumi is a notepad where every line is a calculation. Write "rent = 2450 EUR" and it keeps the number. Write "rent / 4" on the next line and you get each person's share. I use it for trip budgets, splitting bills with housemates, counting hours for invoices and checking how many days are left until a deadline. It handles currencies, units, time and dates, so you can write things like: hotel = 128 EUR per night hotel × 4 prev + 15% total in usd round up 7.2 h 8 h × 5 days days until 25 dec Rp 150rb × 3 "prev" is the line above and "sum" adds up everything above it. Change one number and the rest update. Lines of plain words are just notes, so you can label things the way you like. Currencies: 18 of them, including USD, EUR, GBP, JPY, IDR, SGD, INR and AUD. Rates are built in, so conversion works offline. Units: weight, length, volume, area, speed, temperature, data and energy. There's a…