Multiples, factors and primes N1.3 Core Starter A game is played with a dice which is numbered 3, 5, 6, 9, 10 and 15. There is a board made up of squares numbered from 0 to 100. All players start on 0 and move forward the number of places given by rolling the dice. Players take it in turns to throw the dice and carry on until the winner lands on square 100. Which squares is it impossible to land on? Preamble This activity will encourage systematic working. Some pupils may need to have the rules for moving in a board game explained to them. For some groups, the activity could be simplified to a dartboard with, say, only the numbers 3 and 5 on. The task is then to find which totals from 1 to 100 it is impossible to score (with an unlimited number of darts). Possible content Working systematically, mental addition. Resources 100-square (optional). Solutions/Notes It is impossible to land on 1, 2, 4 and 7. On a dartboard it is also impossible to score 1, 2, 4 and 7.