The children had 20 cards with number sentences on them. They had to work out the totals first, then decide how they would like to order the cards. Some groups put the cards into odd and even answer piles and some ordered them based on the number sentences. 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 practice 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.
