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.
