## Sort Them Out (1)

It's best to do this with $3$ other friends. You can get copies of these cards here: .docpdf

Share all the cards out equally among the four of you.
Work out what the answer is to each question on your cards.
Do you notice anything?
What do you notice?
Try sorting or arranging the cards in some way.

### Why do this problem?

The intention of this problem is that children will work together as a team. It should help in developing mathematical language as well as providing interesting practice in addition and subtraction and possibly offer opportunities to share calculation strategies. It gives ample opportunities to practise calculations using numbers to $20$ and should support children to remember these facts so that they are able to recall and use them whenever they need to do so.

### Possible approach

This sheet will need to be printed out and cut into the fifteen separate cards. You must give out all the cards in the set!

Give out a set of cards to each group of four to six children. (The questions asked in the set do vary in difficulty so you may like to choose who to give specific cards.) To begin with, give children time to work individually on the questions on their own cards. After a suitable period of time, encourage them to ask each other about the questions and answers on other cards. At this stage, members of the group can help each other with the questions, but discourage them from simply giving someone else an answer.

Challenge each group to organise or arrange the cards in some way. At this point, stand back and try not to intervene as they work together. You could invite them to display their cards in their chosen arrangement and then give some time for everyone to move around the room to look at the way each group has sorted the cards.

A short plenary should provide an opportunity for the groups to explain the organisation they chose and for such remarks as "I knew my answer was wrong because it didn't fit in with anyone else's".

### Key questions

Tell me about the number you have found.