Question Video: Using the Counting On Strategy to Add Numbers up to 20 Mathematics • First Year of Primary School

Video Transcript

I have a strange set of dominoes. The dots on one side are hidden by a sticker. The sticker tells you how many dots are hiding under it. What is the total number of dots on this domino?

We have to find the total number of dots. We know there are five on this side, and there are four on the other side. We need to find how many dots there are altogether.

We can use a number line to help us. We know there are five dots on this side of the domino. So we need to start counting at number five. And we’re adding four. So we need to count four more starting at number five.

Count on one, two, three, four. We landed on number nine. Five plus four equals nine. The total number of dots is nine. We started at five on the number line. We counted on four more places and found the answer nine.