Rob LangmanChief Commercial Officer at Third Space Learning

How To Use Near Doubles To Support Mental Calculations

Name: How To Use Near Doubles To Support Mental Calculations
Uploaded: 2024-04-05T09:15:02+00:00
Duration: 1 min 28 s
Channel: Rob Langman
Description: A short instructional clip (YouTube) in which presenter Clare demonstrates the 'near doubles' mental-maths strategy to simplify addition and subtraction…

5 Apr 2024 · 1 min

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1:28

A short instructional clip (YouTube) in which presenter Clare demonstrates the 'near doubles' mental-maths strategy to simplify addition and subtraction. She explains that when two numbers are close to a double (e.g., 35 + 36 is one more than 35 + 35), you can adjust the known double; she gives two worked examples: 35 + 36 = 71 and 30 − 16 = 14.

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Hello, I'm Clare and we're going to look at how to use near doubles as a strategy to help with mental calculations. OK, let's have a look at the question. I've got 35 add 36. Now, I know that that is so close to double 35, it's only one out. If I know that 35 add 35 is 70, then it's very easy for me to work out that 35 add 36 is just going to be one more which will make 71. Let's look at another way in which we can use doubles. Right, on this question, I've got 30 take away 16. That's again so close to 30 take away 15, which is much easier to do because I know that 15 and 15 is going to give me 30. So what I can do is knowing that 30 take away 15 gives me 15, then I can use that knowledge thinking, well, this time I've got to take away 16, which is just one more, so 30 take away 16 is going to give me 14. And that's how we use near doubles to help us work out mental calculations.