Multiplication before addition
In 4 + 3 x 5, we do 3 x 5 first.
This gives 4 + 15 = 19.
Year 6
Perform mental calculations, including with mixed operations and large numbers, and use their knowledge of the order of operations
Use the correct order when a calculation mixes operations, and choose mental strategies when suitable.
Lesson overview
Number - addition, subtraction, multiplication and division
When a calculation contains different operations, multiplication and division are worked out before addition and subtraction unless brackets change the order. Mental calculation is easier when we spot useful number facts and known patterns.
Brackets change the order
In (4 + 3) x 5, we work inside the brackets first.
This gives 7 x 5 = 35.
Worked example
Work out 18 - 4 x 3.
| First | Then |
|---|---|
| 4 x 3 = 12 | 18 - 12 = 6 |
- Multiply first: 4 x 3 = 12.
- Then subtract 12 from 18.
- 18 - 12 = 6.
- So the answer is 6.
Try it
Look for multiplication or division before you start adding or subtracting.
Question 1
4 + 3 x 5 =
Question 2
(4 + 3) x 5 =
Question 3
18 - 4 x 3 =
Question 4
Which calculation equals 24?
multiply first
then add
Question 5
What is the first step in 30 - 12 / 3?
Common mistakes
Watch for these when working through the lesson.
- Adding or subtracting first when multiplication is present.
- Ignoring brackets.
- Doing a mental step too quickly and losing track of the order.
Related topics
These ideas fit closely with this lesson.
- Identify common factors, common multiples and prime numbers.
- Use estimation to check answers to calculations.