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We need to calculate 9.005 minus 3.6, or we could view it

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as 9 and 5 thousandths minus 3 and 6 tenths.

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Whenever you do a subtracting decimals problem, the most

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important thing, and this is true when you're adding

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decimals as well, is you have to line up the decimals.

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So this is 9.005 minus 3.6.

8
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So we've lined up the decimals, and now we're ready

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to subtract.

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Now we can subtract.

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So we start up here.

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We have 5 minus nothing.

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You can imagine this 3.6, or this 3 and 6 tenths, we could

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add two zeroes right here, and it would be the same thing as

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3 and 600 thousandths, which is the same thing as 6 tenths.

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And when you look at it that way, you'd say, OK, 5 minus 0

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is nothing, and you just write a 5 right there.

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Or you could have said, if there's nothing there, it

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would have been 5 minus nothing is 5.

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Then you have 0 minus 0, which is just 0.

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And then you have a 0 minus 6.

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And you can't subtract 6 from 0.

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So we need to get something into this space right here,

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and what we essentially are going to do is regroup.

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We're going to take one 1 from the 9, so let's do that.

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So let's take one 1 from the 9, so it becomes an 8.

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And we need to do something with that one 1.

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We're going to put it in the tenths place.

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Now remember, one whole is equal to 10 tenths.

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This is the tenths place.

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So then this will become 10.

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Sometimes it's taught that you're borrowing the 1, but

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you're really taking it, and you're actually taking 10 from

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the place to your left.

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So one whole is 10 tenths, we're in the tenths place.

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So you have 10 minus 6.

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Let me switch colors.

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10 minus 6 is 4.

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You have your decimal right there, and then you have 8

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minus 3 is 5.

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So 9.005 minus 3.6 is 5.405.

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