Carryover: Mental Math

Carryover: Mental Math is a two-minute mental math run you complete once a day. Every morning the app builds a fresh run out of the levels you have already cleared. Three levels of addition on your second day, everything you own six months in. It never asks you questions you have not been taught, and it never stops getting harder as you go. The run is 120 seconds. A wrong answer costs five seconds rather than ending the attempt, so it stays a test of pace instead of nerve. When the clock runs out you see your score against your own previous runs, and nobody else’s. The daily run is never ranked against other players. Between runs there are the levels themselves: addition, subtraction, multiplication, division and mixed, fifteen levels each, three stars a level. Clear a whole category and its Endless mode opens — one life, no timer, as far as you can get. Endless is the competitive half:…