Math · 5 free levels in the browser · 600 levels in the app
Sangaku were wooden tablets of mathematics hung at shrines in the Edo period, left as offerings for others to solve. Complete the expression on the tablet.
How to play
An equation is displayed with one or more blanks. Evaluate the presented options and tap the value that correctly completes the equation. Higher levels may involve multiple blanks or multi-step operations.
Objective
Complete the equation correctly. Speed and accuracy both contribute to your score.
Strategy tips
Eliminate by magnitude first: if the equation needs a value around 30, cross out any choices below 10 or above 60 before doing exact arithmetic.
For subtraction blanks, rephrase as addition: "12 − ? = 7" becomes "7 + ? = 12" which most people compute faster.
Round and adjust: to get 47 + 36 quickly, compute 50 + 36 = 86, then subtract 3 → 83. This approach is faster than column arithmetic.