You may also like

problem icon

Factoring a Million

In how many ways can the number 1 000 000 be expressed as the product of three positive integers?

problem icon

Thank Your Lucky Stars

A counter is placed in the bottom right hand corner of a grid. You toss a coin and move the star according to the following rules: ... What is the probability that you end up in the top left-hand corner of the grid?

problem icon

Card Game (a Simple Version of Clock Patience)

Four cards are shuffled and placed into two piles of two. Starting with the first pile of cards - turn a card over... You win if all your cards end up in the trays before you run out of cards in one pile. What is the probability that you win?

Sheffuls

Stage: 4 Challenge Level: Challenge Level:2 Challenge Level:2
What letters can you swap that don't make any difference to the spelling?