Or search by topic
Al, Bertie, Chris and Di have sums of money totalling £150.
Al and Bertie have £55 between them and Al and Chris have £65 between them.
What is the difference between the amounts that Al and Di have?
If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.
Can you see how this picture illustrates the formula for the sum of the first six cube numbers?
Brian swims at twice the speed that a river is flowing, downstream from one moored boat to another and back again, taking 12 minutes altogether. How long would it have taken him in still water?
In this problem we are faced with an apparently easy area problem, but it has gone horribly wrong! What happened?