Video Transcript
Try the following method to
calculate multiplications by two. Two times four equals four plus
four, which equals eight. Complete the following: Two times
five equals five plus five, which equals what. And then, use the same method to
complete the following: Two times six equals what.
In this question, we’re shown
several calculations to do with multiplying by two. But we can’t just find the answer
however we like. We’re shown a method or a way of
doing things. And once we’ve understood it, we
need to try it for ourselves to help us find the answers. To begin with then, we’re shown an
example. And this example is all about
finding out two times four.
What does this mean? Well, one way we can think of this
is as two groups of four. Here’s one group of four. Now, we have two groups of
four. We could write this as the addition
four plus four. We could even say double four. And we know that four plus four, or
double four, is equal to eight. So, we’ve used this doubling fact
to help us find that two times four equals eight.
Now that we understand this
doubling method, we can use it again to help us fill in the blanks in these other
calculations. Two times five is the same as two
groups of five or five plus another five. And we know that five plus five, or
double five, equals 10. That’s how we know two times five
equals 10.
Finally, we need to find the answer
to two times six. Two times six is the same as two
groups of six or six plus six. And we know that six plus six, or
six doubled, equals 12. So, two times six equals 12.
In this question, we recognized
that multiplying numbers by two is the same as doubling them. And so, we’ve used addition facts
to help us solve multiplication facts. Two times five is the same as five
plus five, which equals 10. Two times six is the same as six
plus six, which equals 12. Our two missing numbers are 10 and
12.
