Video Transcript
Calculate two times three. Use the answer to the previous
question to help you calculate two times 30. From the answers to the previous
questions, which of the following is equal to two times 30? Two times three, two times three
times zero, two times three times two, two times three times 10, or six plus 10.
This question has three steps to
it. And to start with, you might look
at it and think to yourself, what have all these steps got to do with each
other? They’re asking three different
things, aren’t they? Well, yes, each part does ask us to
do something different, but they’re all related. And hopefully, by the end of this
question, you’ll be able to see how they’re linked and importantly how this very
first, quite easy fact can help us work out something much harder.
So to begin with, we’re asked to
calculate two times three. Hopefully, we don’t have to think
too much about this, do we? Two threes are six. On to the next part. We’re now asked to use the answer
to the previous question, so that’s the number six, to help us calculate two times
30. How can we use the answer to that
simple multiplication to find the answer to this one, which is a lot harder? Well, let’s take a moment to look
at this calculation. We’re being asked to multiply a
single-digit number, two, by a multiple of 10, 30. We know the number 30 is a multiple
of 10 because it’s a number in the 10 times table. It’s worth three 10s. And knowing this is going to help
us.
Two times 30 is the same as saying
two times three 10s. So how many tens is that? Maybe now you can see how the
answer to the previous question can help us. If two times three is six, then two
times three 10s is six 10s. And what are six 10s worth? We just need to multiply our first
answer by 10. Six times 10 equals 60. Our second answer is 10 times as
large as the first one.
In the third part of this question,
we’re asked to use what we’ve done previously in those first two calculations to
help us find a calculation that’s equal to two times 30. So let’s go back right to the start
and talk through what we’ve done. We wanted to find two times 30. We know that 30 is worth three
10s. So first, we found two times
three. This gave us the number of tens in
our answer. And to find the value of our
answer, we then multiplied this by 10. Can you see which one of the
calculations is the same as this? Let’s write it out as we say
it.
First, we found the value of two
times three. As we’ve just said, this gave us
the number of 10s in our answer. And to find the value of our tens
in the answer to our question, we need to multiply this by 10. Two times three times 10 is the
same as two times 30, and we can see why. The number 30 is simply being split
up into three times 10.
In this question, we’ve found how
we could use a fact we already know to help us multiply a one-digit number by a
multiple of 10. If we know two times three, we can
use this to help us find two times 30 because we know our answer will be 10 times
greater. Two times three equals six. And so we know two times 30 must be
equal to 60, which is the same as two times three times 10.