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Operation possible: An easy peasy guide to BIDMAS

Updated: Sep 1, 2023

What is BIDMAS I hear you say? Well, BIDMAS is an acronym (see our guide to acronyms here) that stands for Brackets, Indices, Division, Multiplication, Addition and Subtraction! Oooooh, exciting! So what is it for?

BIDMAS helps us to do things in the right order, because if you don’t you can end up with an incorrect calculation! I know! Nightmare!

First off, let’s learn about equations. An equation is a mathematical expression that contains an equals symbol. Equations often contain algebra too.

Algebra is used in maths when you do not know the exact number in a calculation. Many jobs use equations every day, including air traffic controllers, architects, computer programmers and carpenters!

So let’s break it down, step-by-step so we know what it’s all about.


Brackets always come first, always. This is so that we can put the emphasis on another sum within an equation should we need to, like this (4+5) x 5 = 9 x 5 which gets us 45 instead of 4+25 which is 29. The same numbers but two totally different answers! Phew, those brackets come in handy!

Indices (sometimes called Orders) tell us how many times a number must be used in multiplication, like this 22 which means that you must do 2x2 or this 33 which would be 3x3x3. Another name for this is ‘to the power of’ and this helps to shorten equations. Just remember, indices second!

Division is the dividing operation. As we all know, division is the opposite of multiplication; used to split numbers into an equal amount of parts.

If Jackie has 30 apples, she wants to share them into 5 equal portions for her friends. How many apples does each friend get?

30÷ 5 = 6

Multiplication next! This is all the times-ing you need to do for the equation. 2² + 4 = 8

This is the process of adding a number to itself a specified amount of times to come up with an overall number/product.

2 x 3 = 6

In this case, the answer is found by adding the number 3 twice.

Addition comes next. This operation is where you add a number to another number! Or calculating the total from two or more numbers. For example;

2² + 5 = 9

Subtraction, last but by no means least! The last action within the BIDMAS rule means the number you are left with is what you subtract from.

(4 x 4) - 3 = 13

(Note: Addition and Subtraction are the exception to BIDMAS and you should work these out from left to right in an equation.)

Right! So there you have it, now we can use BIDMAS to bust our equations and become even better mathematicians!

Need another explanation? Here’s a quick video from the BBC to help you!

…and a cool ‘Connect 4’ type game from Transum that uses BIDMAS to place counters! Try it out to help you create the correct calculations and practice!

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