02 Jul 2019

What is BIDMAS: Explained For Primary Parents

  • By Connor Whelan  | 
  • 02 Jul 2019  | 
  • 3 min read
  •  |  Free download

In this post we will be explaining what BIDMAS (and BODMAS) is, what it means, and providing you with some questions you can use to test your KS2 child’s skills when it comes to the order of operations.

What is BIDMAS?

BIDMAS is an acronym to help children remember the order of operations.

You may have also heard of it referred to as BODMAS, but other than the one different letter the acronym remains the same in its meaning.

In maths, an “operation” is what you do to the numbers given. The four main operations are:

  • addition (+);
  • subtraction (-);
  • multiplication (x);
  • and division (÷).

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What does BIDMAS mean?

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 BIDMAS represents.

BIDMAS stands for:

Indices (or “Powers Of” in BODMAS)
Division and Multiplication
Addition and Subtraction

What is BIDMAS: Explained for parents

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 BIDMAS or other areas of KS2 maths?

We hope this post has covered the basic questions like “What is BIDMAS?” 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, so all that’s left for you to do is find the programme that matches your child’s needs, and then watch their confidence in maths blossom!

Examples of the application of BIDMAS

See some examples below of the application of BIDMAS:

Example 1: 6 + 2 x 7

The correct answer to this is 20, as 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).

Example 2: 3 x (2 + 4) + 52

BIDMAS states we should calculate the Brackets first (2 + 4 = 6), then the Indices (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), so the correct answer to this is 43.

This may be commonly miscalculated as 35 by working from left to right.

Example 3: 5 – 2 + 6 ÷ 3

The correct answer to this 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.

BIDMAS and order of operations explained

When will my child learn about BIDMAS in primary school?

Generally, 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.

BIDMAS practice questions for primary school children

1) 29 – 4 x 6 + 5 =

2) Write what the two missing numbers could be. (4 + ?) x ? = 100

3) Write the missing numbers to make these calculations correct.

200 x ? – 200 = 200

(100 – ?) x 100 = 100


BIDMAS KS2 question

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