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.
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".
Tell me about the number you have found.
Have you asked the others in your group about the numbers they have found?
Did you notice anything?
Are you sure that answer is right? How could you check it?
Can you think of a way of arranging the cards?
Learners who find these questions easy may not have solved the problem! How can the cards be organised, arranged or ordered? Such children could help other members of the team check all the answers. Some learners may want to devise their own set of cards to be used in a similar way.
However, if you have a higher-attaining group they could try this similar, but harder, version of the problem
You can purposely give certain cards to certain children if you do not want to take them too far out of their comfort zone where calculation is concerned. It may be appropriate for some learners to share cards with someone who is slightly more confident with addition and subtraction than they are themselves. Encourage them both to feel responsible for thier findings and to involve everyone in the