What is BODMAS And BIDMAS: Explained For Primary School Parents
- By Connor Whelan  |
- 21 Oct 2019  |
- 3 min read
-  |  Free download
What is Bodmas and the Bodmas rule?
The Bodmas rule states that when you are performing a calculation with more than one operation in it the following order of mathematical operations must be followed.
- B Brackets – Complete anything in the Brackets first
- O Orders – Apply any Orders of, indices, square roots etc
- D / M Division and Multiplication – Then do any division or multiplication (if both apply, follow left to right order)
- A / S Addition and Subtraction – Finally do the addition or subtraction part of the calculation (again, if both apply follow left to right order)
BODMAS (or BIDMAS) is an acronym used to help students remember the order of operations. In this post we cover what it means, and provide you with some BODMAS questions and exercises you can use to help your KS2 child practise accurately carrying out BODMAS calculations.
What is BODMAS?
The BODMAS rule is an acronym to help children remember the order of mathematical operations – the correct order in which to solve maths problems. Some children also use it as a mnemonic (like Richard Of York Gave Battle In Vain is used to remember colours)
You may have also heard of it referred to as BIDMAS, but other than the one different letter the BODMAS or BIDMAS rule remains the same in its meaning.
“Mathematical operations” are what you do to the numbers given. The four main operations are:
- addition (+);
- subtraction (-);
- multiplication (x);
- and division (÷).
When presented with a number sentence containing more than one operation (such as 3 + 4 x 2) the operations cannot be completed from left to right, but instead in their order of “importance”, which is what BODMAS stands for.
BODMAS stands for:
“Orders” means square roots and indices (which you may know as square numbers, powers or exponents).
BIDMAS stands for:
Here “Indices” (square numbers, powers or exponents) are used instead of Orders.
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What does order of operations mean?
This is the order in which certain operations must be completed, from brackets first to addition and subtraction last.
It is important that division and multiplication are represented alongside each other as they are of equal importance (so must be completed from left to right, whichever appears first) – this is the same for addition and subtraction.
Does your child need help with BODMAS or other areas of KS2 maths?
This post covers the basic questions like “What is BODMAS?” and “What does BIDMAS mean?”, but if your child needs more in-depth maths help then take a closer look at Matr’s primary maths programmes.
We have different programmes designed for children in all primary year groups; the starting point is one to one lessons with a personal tutor. Try your free lesson here.
Below are some examples of BODMAS questions and answers children might see in schools. We’ve given you the right answer and at least one different answer to show you where children might go wrong.
BODMAS (BIDMAS) Questions and Answers
Question 1: 6 + 2 x 7
The correct answer is 20.
The multiplication must be completed first (2 x 7 = 14) and then the addition (6 + 14 = 20).
This may be commonly miscalculated as 56 by working from left to right (6 + 2 = 8, 8 x 7 = 56).
Question 2: 3 x (2 + 4) + 52
The correct answer is 43.
The BODMAS rule states we should calculate the Brackets first (2 + 4 = 6), then the Orders (52 = 25), then any Division or Multiplication (3 x 6 (the answer to the brackets) = 18), and finally any Addition or Subtraction (18 + 25 = 43).
Children can get the wrong answer of 35 by working from left to right.
Question 3: 5 – 2 + 6 ÷ 3
The correct answer is 5.
The division must be completed first (6 ÷ 3 = 2) which then leaves addition and subtraction; as both are of the same importance, we can then work from left to right. 5 – 2 + 2 (the answer to 6 ÷ 3) = 5.
This may be commonly miscalculated as either 3 by working from left to right, or as 1 by wrongly assuming that addition should be completed before subtraction.
When will my child learn about BODMAS in primary school?
BODMAS is taught in upper KS2 and often primary school children won’t come across the order of operations until Year 6
The national curriculum states that Year 6 pupils should be taught to use their knowledge of the order of operations to carry out calculations involving the four operations.
The non-statutory guidance advises that pupils explore the order of operations using brackets; for example, 2 + 1 x 3 = 5 and (2 + 1) x 3 = 9.
As a parent trying to support your child with order of operations questions you’ll find that most calculators and computers nowadays are sophisticated enough to complete calculations according to BODMAS. However it’s worth testing any calculator out just to be sure. There are also plenty of BODMAS calculators available online.
Practice KS2 BODMAS questions
1) 29 – 4 x 6 + 5 =
2) Write what the two missing numbers could be. (4 + ?) x ? = 100
Answer: 6 and 10 (4 + 6) x 10 = 100
3) Write the missing numbers to make these calculations correct.
a) 200 x ? – 200 = 200
b) (100 – ?) x 100 = 100
Answers: a) 2 b) 99
4) Write the correct sign >, < or = in each of the following
a) (10 + 5) – 9 [ ] (10 + 9) – 5
b) 3 x (4+5) [ ] (3 x 4) + 5
c) (10 x 4) / 2 [ ] 10 x (4 / 2)
a) (10 + 5) – 9 < (10 + 9) – 5
b) 3 x (4+5) > (3 x 4) + 5
c) (10 x 4) / 2 = 10 x (4 / 2)
Practice Year 6 BODMAS questions
Looking for further BODMAS worksheets and support?
As part of the Matr online maths programme your child will be taught one to one by a tutor, and together they will work through BODMAs questions like these.
You will also then be able to access over 100 maths worksheets from our online resource library to support them with their maths homework. We’re offering all readers of our blog a free one to one maths lesson – start your free trial here.
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