Making 100

1) Odd one out

2) Starter exam question see flipchart or picture below

3) Grid - get pupils to draw a 2 by 2 grid. Using the digits from 1-9 pupils put a different digit in each box in the grid

For example

From this read 2 numbers horizontally - (58 and 72) and 2 numbers vertically down (57 and 82). Get pupils to add these 4 numbers together. Dis cuss how they added the numbers up. Look at different methods. Did anyone get more than 100? Less than 100? Did anyone get 100? (There is more than 1 method)

Get pupils to then see if they can make 100. Try as many as they can.

4) Go through any grids where pupils have made 100. Talk about why these grids have made 100. What strategies did they use? Which values contribute to the units and which contribute to the tens?

EXTENSION

What is the biggest possible number that could be made?

What is the smallest possible number that could be made?