Topics
4. Multiplication and division
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AustraliaNSW
Stage 2

4.04 Multistep problems

Lesson
Practice
Lesson

Are you ready?

We have learned to write a number problem from a  story problem with multiplication or division  already.

Examples

Example 1

There are 3 rows of trees in a field, with 10 trees in each row.

a

Write a number sentence for this story problem.

Worked Solution
Create a strategy

There are an equal number of trees in each row, so we can think of each row as a group.

Apply the idea

There were 3 groups of 10 trees, and "groups of" means multiply.

Number sentence =3\times 10

b

How many trees are there in the field?

Worked Solution
Create a strategy

We can find the number of trees in the field by solving the number sentence in part (a).

Apply the idea

3\times 10 = 30

There are 30 trees.

Idea summary

If we have a number of equally sized groups, we need to multiply to work out the total.

Multi-step problems

What happens if our story has more than one part to it? Let's see how to turn that into a number problem with multiplication and division.

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Examples

Example 2

There are 2 flower beds in Irene's backyard. Each flower bed has 4 strawberry plants.

a

How many strawberry plants are there in total?

Worked Solution
Create a strategy

There are 2 groups of 4 strawberry plants. "Groups of" means multiply.

Apply the idea
\displaystyle \text{Total strawberry plants}\displaystyle =\displaystyle 2\times 4Multiply 2 by 4
\displaystyle =\displaystyle 8
b

If each plant has 3 strawberries growing on it, how many strawberries are there in total?

Worked Solution
Create a strategy

Multiply the number of strawberry plants in part (a) by the number of strawberries on each plant.

Apply the idea
\displaystyle \text{Strawberries}\displaystyle =\displaystyle 8\times3Multiply 8 by 3
\displaystyle =\displaystyle 24
Idea summary

We can use pictures, numbers or symbols for our problems, so it helps to know how to use each method.

The image shows 3 times 4 in pictures, words and symbols. Ask your teacher for more information.

Outcomes

MA2-6NA

uses mental and informal written strategies for multiplication and division

MA2-8NA

generalises properties of odd and even numbers, generates number patterns, and completes simple number sentences by calculating missing values

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