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Times tables up to 12 x 12

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Mental maths strategies

Common factors and multiples

Order of operations: BIDMAS

Using estimation to check answers

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Adding numbers using mental maths

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Using column subtraction to subtract numbers

Multi-step problems with addition and subtraction

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Numbers to 10,000,000

Place value: Four-digit numbers

Representing numbers in different ways

Rounding any number up to 1,000,000

Counting using positive and negative numbers

Counting in powers of 10

Negative numbers

Explainer Video

Tutor: Labib

Summary

Mental maths strategies

In a nutshell

Mental calculations can be performed faster by reorganising calculations into an easier format.

Commutative property

The commutative property means that the order in which you multiply or add numbers will have no effect on the answer.

Example 1

Demonstrate the commutative law with $4 \times 3$ .

Calculate $4 \times 3$ .

$4\times 3 = 12$

Reorder the numbers to $3 \times4$ .

$3 \times 4 =\underline{12}$

Note: The commutative property can be applied even if there are more than two numbers being multiplied together.

Factor pairs

Factor pairs are two whole numbers which multiply to give the original number. Factor pairs can be used to break up a multiplication into easier steps.

Example 2

How many factor pairs does $12$ have?

Find all the whole numbers which multiply to give $12$ .

${\begin{aligned} {12 \times1 = 12} \\ {6 \times 2=12}\\ {4 \times 3=12} \end{aligned}}$

There are $\underline{3}$ factor pairs for $12$ .

Note: The commutative property means the factor pairs can be written in the opposite order.

Example 3

Calculate $7 \times 16$ .

$16$ can be split into $8$ and $2$ . Use this to work out $7 \times 16$ .

$7 \times 8 \times 2$

Multiply the numbers in an order you find easy.

$\begin{aligned} 7\times 8 &= 56 \\ 56 \times 2 &= 112 \\ \\ &or \\ \\ 7 \times 2 &= 14 \\ 14 \times 8 &= 112 \end{aligned}$ 

Therefore, $7 \times 16 = \underline{112}$ 

Note: $7$ is a prime number which means its only factor pair is $1$ and $7$ .

Learn with Basics

Length:

Unit 1

Multiplying and dividing by 2, 3, 4 and 8

Unit 2

Times tables up to 12 x 12

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Unit 3