Year 3

We can add and subtract multiples of 10 or 100 in our head.
We know number pairs that total 100.

Year 3 Unit 8

What we are learning:

• Multiples of 10 have 0 units. 10, 20, 30, 40 ….
• Multiples of 100 have 0 tens and 0 units. 100, 200, 300, 400 …
• Mathematicians sometimes refer to the pairs of numbers that total 100 as the ‘complements’ to 100 (50 and 50, 32 and 68, 94 and 6 etc)

ACTIVITY 1: 100 SNAP, A GAME OF NUMBER PAIRS THAT TOTAL 100

ACTIVITY SHEETS

Downloads:

Activity sheet: 100 Snap PDF

ACTIVITY 2: PAIRS WHICH TOTAL 100 GAME

Activities you can do at home:

Cut out a selection of shapes (circles, squares, triangles, hearts etc) cut them roughly in half using a zig-zag line. On each ‘half’ write matching complements to 100 – so you may cut a heart roughly in half and on one side write 60 and on the other side 40.
These shapes can then be jumbled up and given your child to discover the complements to 100. The shapes will support them in their discovery and if you cut out a few of each shape the zig-zag cut will ensure they have to get an exact match for the complements to be correct (like a simple jigsaw).

Play complements to 100 snap (cut out cards on sheet “100 snap”) say snap when the 2 cards total 100.

Write down 100 in the middle of a sheet of paper. Draw a circle round it. Give your child a few minutes (vary the time given according to how confident they are) to write down all of the complements to 100. Doing this regularly will speed up their recall of key facts.

Good questions to ask:

What do all multiples of 10 end in?
What do all multiples of 100 end in?
How do we know whether a number is a multiple of 10?
How do we know whether a number is a multiple of 100?

If your child:

Knows the multiples of 10 that add to 100 in pairs, e.g. 20 and 80, 60 and 40 but struggles to see the other pairs, e.g. 28 and 72
Do not worry. If they can work them out that is fine and they will become more familiar with practice over time.