Wednesday 11th August – Maths

Subtraction Using the Counting Back Strategy

I am learning to use the counting back strategy to solve subtraction problems.

I know I can do it when I am counting back from the biggest number in a subtraction problem.

This week we are looking at solving subtraction problems, focusing on counting back from the largest number. Learning to do this allows us to subtract from a collection of objects much quicker.

Watch this video to learn more: ā†“ā†“ā†“

Independent Task

To complete today’s task, you will need some playing cards or two dice. If you don’t have any, follow this link for some online dice.

Using cards:

  • Remove all of the picture cards and the 10s from your deck so that you only have Aces through to 9s.
  • Choose two cards from your deck (eg. 3, 4).
  • starting from the biggest number, use the counting back strategy to work out what you would have left if you subtracted the smallest number from the largest number (4-3=1).
  • On a piece of paper, write down the subtraction problem that you have solved.

Using dice:

  • Roll two dice (10 sided if you have them)
  • starting from the biggest number, use the counting back strategy to work out what you would have left if you subtracted the smaller number on the dice from the largest number on the dice (4-3=1).
  • On a piece of paper, write down the subtraction problem that you have solved.

Repeat this process at least 5 times.

Adjusting This Task For You!

If you wish to challenge yourself, you could try to use mental strategies to subtract 2-digit numbers.