Rob LangmanChief Commercial Officer at Third Space Learning

Teach Subtraction By Counting Back In Hundreds, Tens, And Ones

Name: Teach Subtraction By Counting Back In Hundreds, Tens, And Ones
Uploaded: 2024-04-04T07:51:05+00:00
Duration: 1 min 42 s
Channel: Rob Langman
Description: A short instructional video in which Brooke teaches primary-school subtraction by demonstrating the informal counting-back method on a number line. Using…

4 Apr 2024 · 2 min

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A short instructional video in which Brooke teaches primary-school subtraction by demonstrating the informal counting-back method on a number line. Using the example 'Ellie has 276 stickers, loses 135', Brooke partitions 135 into hundreds, tens, and ones (100, 30, 5) and shows stepwise subtraction (276→176→146→141), noting parts may be subtracted in any order to build number fluency.

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Hi, my name's Brooke. And in this video, we're going to be subtracting using the informal method of counting back in hundreds, tens, and ones. So let's have a look at our question. Ellie has 276 stickers, but she loses 135. How many stickers does she have left? So, first of all, I'm going to start off by drawing my number line and putting 276 here. Now, pupils should realize that we're taking away the number 135. And to do that, we need to partition it into hundreds, tens, and ones. So I'm going to start off by taking away 100. I've counted back 100 to 176. I'm then going to count back three tens, one, two, three, to 146. And then finally, I need to count back five ones to 141. Now, the number line helps to reinforce the fact that we're counting backwards. But eventually, pupils will be able to do this without. You can also write down each calculation as you go. So 276 take away 100 equals 176. And then 176 take away the three tens equals 146. And then 146 take away the five ones equals 141. A great way to build number fluency is to show that you can do it in any order. So you might start off by taking the ones, then the hundreds, and then the tens. And that's how to subtract informally using the method of counting back.