This is a nifty little investigation to help with addition of three  single digit numbers as well as logical thinking. Ten cards are shown, with the numbers from zero to nine. The task is simple, find three cards that make a total of 12. (eg 7 + 3 + 2). The challenge is to find 10 different ways of doing this, using only one of each number each time. So 8 + 2 + 2 would not count as it uses the 2 card twice. There are surprisingly few ways of doing this ( 10 in fact) and it is recommended that children work in pairs to help each other find all ten solutions. Discussion in this type of task is important as it helps children both with listening skills and explaining what they are trying to do, which in turn helps them clarify their thinking. If this problem is solved can they think of another similar problem eg using 4 cards. Will this mean more possible solutions or less? Go to our 3 card challenge