Tables 2, 3, 4, 5 and 10 | Year 3

01 / LEARN

Understand the idea.

Facts describe equal groups

A multiplication fact describes equal groups. In $4 \times 3$ , think of four groups with three in each. Count the groups: $3$ , $6$ , $9$ , $12$ . The total is twelve, rather than the sum of four and three.

The $2$ , $3$ , $4$ , $5$ and $10$ tables all use this meaning. Keep each group the same size. When groups have different sizes, add their separate amounts instead of treating them as identical groups.

Use a fact you know

Build an unfamiliar fact from a known one. Four groups contain twice as much as two groups of the same size. For example, double the answer to $2 \times 7 = 14$ to find $4 \times 7 = 28$ .

Five equal groups contain half as much as ten equal groups. You can also move to the next fact by adding one group: from $5 \times 3 = 15$ , add another $3$ to get $6 \times 3 = 18$ .

02 / WORKED EXAMPLES

See the method in action.

EXAMPLE 01

Double a known fact

Use 2 × 8 = 16 to find 4 × 8.

Worked solution

1
Use the known total for two groups.
$2 \times 8 = 16$
The question gives the total of two groups of eight.
2
Double that total.
$16 + 16 = 32$
Four groups are two groups together with another two groups.
3
State the new multiplication fact.
$4 \times 8 = 32$
The group size stays eight while the number of groups doubles.

Answer

4 × 8 = 32

EXAMPLE 02

Use the ten-times table

Find 5 × 9 using 10 × 9.

Worked solution

1
Find the total for ten groups of nine.
$10 \times 9 = 90$
The ten-times table gives ninety.
2
Halve the total.
$90 \div 2 = 45$
Five groups are half as many as ten groups of the same size.
3
State the five-times fact.
$5 \times 9 = 45$
Halving the number of equal groups halves their total.

Answer

5 × 9 = 45

03 / YOUR TURN

Try it yourself.

Check your understanding

Find 7 × 3 using 6 × 3 = 18.

Show answer & reasoning

Seven groups of three contain one more group than six groups. Add $3$ to the known total: $18 + 3 = 21$ .

Keep practising

6 worksheet questions

Open worksheet Worked solutions

Read the questions online

Calculate $8 \times 2$ .
Calculate $6 \times 3$ .
Calculate $9 \times 4$ .
Calculate $7 \times 5$ .
There are 8 boxes with 10 crayons in each. How many crayons are there?
Explain how $5 \times 4 = 20$ helps you find $6 \times 4$ .

Read the worked solutions

Calculate $8 \times 2$ .
Eight twos make 16.
16
Calculate $6 \times 3$ .
$3 + 3 + 3 + 3 + 3 + 3 = 18$ .
18
Calculate $9 \times 4$ .
$9 \times 2 = 18$ , then double 18 to get 36.
36
Calculate $7 \times 5$ .
$7 \times 10 = 70$ ; half is 35.
35
There are 8 boxes with 10 crayons in each. How many crayons are there?
$8 \times 10 = 80$ .
80 crayons
Explain how $5 \times 4 = 20$ helps you find $6 \times 4$ .
Add one more group of four: $20 + 4 = 24$ .
$6 \times 4 = 24$ .

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Curriculum reference & lesson scope

Australian Curriculum v9 / SA Curriculum Mathematics

Tables 2, 3, 4, 5 and 10; linked division; arrays; one-/two-digit problems.

Official curriculum source ↗

In this lesson

Understand the idea.

Facts describe equal groups

Use a fact you know

See the method in action.

Double a known fact

Use the known total for two groups.

Double that total.

State the new multiplication fact.

Use the ten-times table

Find the total for ten groups of nine.

Halve the total.

State the five-times fact.

Try it yourself.

Check your understanding

Keep practising