# Count On

## Explorer

#### Puzzle of the Day

These puzzles are also printed in Eight days a week, a booklet published by the Association of Teachers of Mathematics.

How many ways can you find to make the number 10, by adding or subtracting prime numbers? The same numbers but in a different order count as the same answer. (Prime numbers are only divisible by themselves and 1 so they are 2, 3, 5, 7, 11, 13, ...)

Answer: 2+3+5, 2+2+3+3, 3+7, 5+5,13-3, 17-7, 23-13 etc