Pairs of numbers

If you have ten counters numbered 1 to 10, how many can you put into pairs that add to 10? Which ones do you have to leave out? Why?

Problem

Pairs of Numbers printable sheet

 

Image

If you have ten counters numbered 1 to 10, how many can you put into pairs that add to 10?

Can you use them all?

Why or why not?

 

Now put the counters into pairs to make 12.

  • Can you use them all?
  • Why or why not?

Now put the counters into pairs to make 13.

  • Can you use them all?
  • Why or why not?

Now put the counters into pairs to make 11.

  • Can you use them all?
  • Why or why not?