Question Video: Dividing Three-Digit Numbers by One-Digit Numbers Using the Partial Quotient Method Mathematics • 4th Grade

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Video Transcript

Evaluate 216 divided by eight. Hint: use partial quotients to help you.

In this question, we need to find the answer to 216 divided by eight. And we’re given a hint. We’re told that we can use partial quotients to help us. In other words, instead of thinking about how many eights there are in 216 eight at a time, we can split the number 216 into parts. And we can find the answer one chunk at a time. So to begin with, let’s write out our calculation. And the way we do this is by putting down the divisor. That’s the number we’re dividing by first. Then we draw a series of lines. It will always look exactly like this. This is one way to draw it. And then underneath the top line, we write the large number that we’re dividing.

So this calculation asks us, “How many eights are there in 216?” Now what multiples of eight could we take away from 216 to take us down to zero quickly? We could subtract eight, then eight, then eight, then eight, and so on, but that would take a really long time. A fact that we could use to help us is 10 eights. 10 eights are worth 80. But you know, we could get even closer to 216 if we double this fact. If we know 10 eights are worth 80, then 28 must be worth double 80 or 160. Now we can definitely see that there are 20 eights in 216. So let’s take away 160 straightaway.

Now 216 take away 100 leaves us with 116. And if we take away 60, this takes us back to 56. And so we can say 216 take away 160 equals 56. Now we know how many eights are in 56, don’t we? This is a times table that we’ve already learned. There are seven eights in 56. And so if we take away our last seven eights, we’re going to be left with nothing.

We’ve used partial quotients to help us find how many eights there are in 216. And we took away 20 lots of eight and then another seven lots of eight. And that’s how we know 216 divided by eight equals 27.