Question Video: Using the Counting Back Strategy to Subtract from Numbers up to 20 Mathematics • Second Year of Primary School

Video Transcript

On this domino, the dots on one side are covered with a sticker, and the total number of dots is written above it. How many dots are under the sticker on this domino?

We know that there are 11 dots altogether on this domino. We can see half of the domino. It has one, two, three, four dots showing. If we take those four away from 11, it will tell us how many dots are underneath the sticker. We could start at 11 on our number line and count back four. Counting back is the same as taking away. We start at 11, 10, nine, eight, seven, 11 take away four is seven. There would be seven dots underneath the sticker. Seven plus four is 11. 11 take away four equals seven.