SOROBAKMental arithmetic

Choose the next step

Choose the number
range

Practise the friends-of-five formulas and become faster and more confident with every step.

F5 Selected modeFriends of 5

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