Ask a friend to pick a random number, add this, subtract that-and presto, astound your friend by guessing the new number! Math riddles, mental math tricks, magi

Maths with the laughs added in! \* Why nothing sometimes means something? \* Can you beat Professor Fiendish's foul formula? \* What can stop a hairy green spot

Provides instructions for shortcuts of varying degrees of difficulty for doing arithmetical calculations and estimates, and for checking answers.

Murderous Maths: The Secrets of Sums is full of facts, tricks and tips to help children discover why numbers are nifty and arithmetic is amazing. Updated for th

These simple math secrets and tricks will forever change how you look at the world of numbers. Secrets of Mental Math will have you thinking like a math genius