Two Numicon® shapes – which shapes are in the Christmas sack?
Show me 2 shapes that could be in the sack. Why do you think that? Are you sure? Convince me.
Are they the only 2 shapes it could be?
How many pairs could it be?
If I show you one of the shapes will you know for sure what the other one is?
Encourage children to explain their reasoning. At first, why don’t they know for sure which two shapes are in the sack? How many possible pairs can it be? Show one pair, and another, and another………..
When you know one shape, how can you be sure what the other shape is?
Variations
- Put one shape in the sack and give children clues so that they can work out which shape it is. An opportunity to model mathematical language. My shape is:
- one more / one less than………
- two more/ two less than………
- in between……
- an odd/even number
- If I add …and …..I get this number
- If I take my number away from 10, I am left with……
- The difference between my number and 6 is………
- ……more than……
- a multiple of ……….
- a factor of………Get the children to ask questions about your shape to work out which one it is.
- Put 3 shapes in the sack. The total is 15 which shapes could they be? What if I show you 1 shape, how does that change your thinking?
- Vary the totals, vary the number of shapes.
Digit Dog Challenges 