SOROBAKMental arithmetic

Choose the next step

Choose the number
range

Master the friends-of-ten formulas while maintaining speed and accuracy.

F10 Selected modeFriends of 10

4 levels

Where should we start?

Start at a comfortable level. You can return and choose another at any time.

One digit

Fast, confident calculation with one digit

Two digits

Focus training with two-digit numbers

Three digits

Larger numbers and a stronger memory

Four digits

Maximum difficulty and accuracy