Find seven multiplied by three. Hint: How can knowing five times
three help you?
In this question, we have to find
seven multiplied by three. And we’ve been given this model to
help us. And we’re also given a hint that
tells us to think about how knowing five times three can help us to find seven times
three. This model shows three lots of
seven cubes. Did you notice how the seven has
been broken apart into five cubes and two cubes? We know that we can partition the
number seven into five and two because five and two make seven. So, we can find seven times three
by first multiplying five by three and then multiplying two by three.
What is five times three? Five times three is 15. Now, we can calculate two times
three, which is six. And if we add 15 and six together,
we get 21. We found seven times three by
partitioning or breaking the number seven apart into five and two. First, we found five times
three. Then, we found two times three. We multiplied each part by
three. And we can add the parts back
together again to find the product of seven times three. If five times three is 15 and two
times three is six, then seven times three is 21.