Number (mult/div)

Lesson

When we work with written problems, we may need to go through them more than once, to find the information we need. Some things to think about are:

- Are we
*combining*equal groups to get a total? - Are we
*sharing*, or 'dividing up' what we have? - Are there any numbers, or pieces of information, that we actually
*don't need*?

Let's see how we can turn our written problem into a number problem, like we did when we looked at numbers up to 10. This time though, we can build on that knowledge to work on numbers up to $15$15.

The next step is to have some strategies to solve the number problems. We can identify words or sentences that tell us if we need to multiply or divide, and then we can use strategies such as the distributive law of multiplication, and dividing by 10 to help us solve our problem.

In the first video, we'll find out what our multiplication number problem is. Then, when things change, we can use division to solve the new problem we are faced with.

In our second video, we need to share things among groups, so we will start with division. Dividing by 10 helps us work out an estimate for our answer first, then we can use our 12 times tables to work towards our answer. We also see just how multiplication and division are linked in this video.

Remember!

When we know our total, and need to share into groups, we use division. If we need to work out a total, then we use multiplication.

Solve problems that arise from real-life situations and that relate to the magnitude of whole numbers up to 100 000

Solve problems involving the addition, subtraction, and multiplication of whole numbers, using a variety of mental strategies (e.g., use the commutative property: 5 x 18 x 2 = 5 x 2 x 18, which gives 10 x 18 = 180)