Addition and subtraction

problem
The Pied Piper of Hamelin

Age

7 to 11

Challenge level

This problem is based on the story of the Pied Piper of Hamelin. Investigate the different numbers of people and rats there could have been if you know how many legs there are altogether!
problem
Adding plus

Age

7 to 11

Challenge level

Can you put plus signs in so this is true? 1 2 3 4 5 6 7 8 9 = 99 How many ways can you do it?
problem
Cherries come in twos

Age

7 to 11

Challenge level

Susie took cherries out of a bowl by following a certain pattern. How many cherries had there been in the bowl to start with if she was left with 14 single ones?
problem
Numbered cars

Age

7 to 11

Challenge level

Can you crack my code and use it to find out what two car number plates add up to?
problem
All seated

Age

7 to 11

Challenge level

Look carefully at the numbers. What do you notice? Can you make another square using the numbers 1 to 16, that displays the same properties?
problem
A numbered route

Age

7 to 11

Challenge level

Can you draw a continuous line through 16 numbers on this grid so that the total of the numbers you pass through is as high as possible?
problem
Finding fifteen

Age

7 to 11

Challenge level

Tim had nine cards each with a different number from 1 to 9 on it. How could he have put them into three piles so that the total in each pile was 15?
problem
Function machines

Age

7 to 11

Challenge level

If the numbers 5, 7 and 4 go into this function machine, what numbers will come out?
problem
The twelve pointed star game

Age

7 to 11

Challenge level

Have a go at this game which involves throwing two dice and adding their totals. Where should you place your counters to be more likely to win?
problem
Magic matrix

Age

7 to 11

Challenge level

Find out why these matrices are magic. Can you work out how they were made? Can you make your own Magic Matrix?