Identity property of 1

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Maths3rd grade (Eureka Math/EngageNY)1:242 check-ins

About this video

The video multiplies 65 by 1 and shows it can mean one 65 or 1 added sixty-five times, giving 65 either way. It explains that any number times 1 is that same number, with examples like 3, 5 and 157.

You'll be able to

  • explain what multiplying by 1 means.
  • multiply any number by 1 without calculating.

Key words

times 1
Having one group of a number, so you get the same number back.
placeholder
A blank or shape that stands for any number.
Transcript

We're asked to multiply 65 times 1. So literally, we just need to multiply 65-- we could write it is a times sign like that or we could write it as a dot like that-- but this means 65 times 1. And there's two ways to interpret this. You could view this as the number 65 one time or you could view this as the number 1 sixty-five times, all added up.

But either way, if you have one 65, this is literally just going to be 65. Anything times 1 is going to be that anything, whatever this is. Whatever this is times 1 is going to be that same thing again. If I have just some kind of placeholder here times 1, and I could even write it as the times symbol times 1, that's going to be that same placeholder.

So if I have 3 times 1, I'm going to get 3. If I have 5 times 1, I'm going to get 5, because literally, all this is saying is 5 one time. If I put-- I don't know-- 157 times 1, that'll be 157. I think you get the idea.

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