Mental calculations

This problem is designed to help children to learn, and to use, the two and three times tables.

Here are some short problems for you to try. Talk to your friends about how you work them out.

Can you use the information to find out which cards I have used?

How many ways can you find to put in operation signs (+, −, ×, ÷) to make 100?

What is the smallest number of answers you need to reveal in order to work out the missing headers?

Tom and Ben visited Numberland. Use the maps to work out the number of points each of their routes scores.

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?

What happens when you add the digits of a number then multiply the result by 2 and you keep doing this? You could try for different numbers and different rules.

This group activity will encourage you to share calculation strategies and to think about which strategy might be the most efficient.

Can you each work out the number on your card? What do you notice? How could you sort the cards?