Video: Counting Backward on a Number Line to Subtract

Skip count backward by 5s to subtract 5. What is 18 take away 5? What is 13 take away 5? What is 8 take away 5?

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Video Transcript

Skip count backward by fives to subtract five. What is 18 take away five? What is 13 take away five? And what is eight take away five?

The question tells us to skip count backward by fives to help us subtract five each time. And we can see the first subtraction has already been done. We started at 23 and skip counted backward by five, 23, 22, 21, 20, 19, 18. 23 take away five is 18. We skip counted backward by fives to help us subtract five.

Next, we need to calculate 18 take away five. So, we need to start at 18 and skip count backward by fives to subtract five, 18, 17, 16, 15, 14, 13. 18 subtract five is 13. Next, we have to calculate 13 take away five. Start at 13 and count backward by five, 12, 11, 10, nine, eight. 13 subtract five is eight.

Now we just need to work out the final calculation eight take away five. We need to start at eight and count back five, seven, six, five, four, three. We used the number line to help us skip count backward by fives to subtract five. 18 take away five is 13. 13 take away five is eight. And eight take away five is three.