3. Multiplication and division

Lesson

We've seen how to write a multiplication or division problem , by finding clues in our story problems, such as sharing, or groups of.

Dylan has 120 chocolates to give out to 10 guests at his birthday party and wants to make sure each guest gets the same amount.

Write a number sentence for this story problem to find how much each guest would get.

Worked Solution

Idea summary

If we know our total and want to find out how many groups we have, or how many are in each group, we need to divide.

We may see some different clues in our story problems, so we need to figure out if we need to multiply or divide.

An apartment block is 36 metres tall and a house is 6 metres tall.

How many times smaller is the house than the apartment block?

Worked Solution

Idea summary

For story problems, we need to look for key words that tell us what we need to do.

Let's look at some written problems, and rewrite them as number problems. We also solve a problem where we need to change some of our information into a **value** we can use.

Max's Motors sold 49 cars in a 7-day week.

a

If they sold the same number of cars every day, write a number sentence to show how many cars they sold each day. Use the (\div) symbol.

Worked Solution

b

How many cars were sold each day?

Worked Solution

Idea summary

If we have a total to share, we use division to work out how many groups, or how many in each group.

When you are solving division story problems, you may still end up with a remainder.

A show bag costs \$7.

a

How many show bags can I buy with \$31?

Worked Solution

b

How much money will I have left over?

Worked Solution

Idea summary

Words that suggest finding the total of a number of equally sized groups of something indicate

**multiplication**.Words that suggest sharing into equal groups will require us to use

**division**.

Solve problems involving multiplication of large numbers by one- or two-digit numbers using efficient mental, written strategies and appropriate digital technologies

Solve problems involving division by a one digit number, including those that result in a remainder

Use efficient mental and written strategies and apply appropriate digital technologies to solve problems