Find the shorter route.

Free mental-math practice: turn awkward calculations into manageable steps. Start with RFD, practise ×11, then build up to two- and three-digit multiplication with B11.

Try the idea: 48 + 29 = 48 + 30 − 1 = 77. Round 29 up by 1, then subtract that extra 1.

Start here: RFD

Free · No account · Practise at your own pace

A useful route depends on the problem. Learn the method, then choose what works for you.

01 · Foundation

RFD Training

Rebuild addition, subtraction, multiplication, and division as friendlier calculations.

02 · Tool

Killer Move ×11

Multiply by 11 using neighbouring digit sums and carries — the Killer Move used throughout B11.

03 · Bridge

B11 Soft

Apply the method step by step with a two-digit B11 factor.

04 · Method

Full B11

Code a three-digit factor and execute the complete Killer Ladder.