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  • - [Instructor] Let's say that we want to figure out

  • what is seven and 11/12 minus one and 6/12.

  • Pause this video and see if you can figure that out.

  • All right now let's work on this together.

  • So there's a couple of ways that you could approach this.

  • You can view this as the same thing as seven plus 11/12

  • and then minus one and you might be tempted to say minus

  • one and then plus 6/12 but remember you're subtracting

  • not just the one you're subtracting one and you're

  • subtracting 6/12 so minus one minus 6/12.

  • Now why is that useful to think about it that way?

  • Well now you can think about the whole numbers so you can

  • say this is going to be seven minus one plus 11/12,

  • plus 11/12 minus 6/12, minus 6/12.

  • And so seven minus one is six, so it's going to be six plus

  • now if I have 11 of something in this case 12ths

  • and I'm subtracting six of them away six of the 12ths,

  • I'm gonna be left with five of those somethings, five 12ths.

  • So it's going to be six plus 5/12 which is the same thing

  • as six and 5/12.

  • Now as you get more used to this you could do some

  • of this maybe even in your head, you could say hey look,

  • look at the whole number parts, seven minus one is going

  • to give me six and then if I say 11/12 minus 6/12

  • is going to give me 5/12 so that takes up a little bit

  • less space.

  • Another way that you might see this approached is you can

  • rewrite this as seven and 11/12 minus, minus one and 6/12.

  • Let me do the 6/12 in that blue color that I'm using

  • for the fraction parts, 6/12 and then I would first

  • focus on the fractional parts and I'd say 11/12 minus 6/12

  • is 5/12 and seven minus one is six and I got six and 5/12.

  • So many different ways to approach the same thing

  • and at the end of the day they really are the same

  • underlying idea.

- [Instructor] Let's say that we want to figure out

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A2 subtracting approach subtraction tempted figure approached

Mixed number subtraction

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    林宜悉 posted on 2020/03/27
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