tales from the chalk face

BODMAS – one of my favourite topics to teach.

2 + 3 x 4

Does it equal 20 or does it equal 14?

We can’t have two answers to one question – that would cause all sorts of confusion!

So, back in the day, mathematicians got together and agreed to BODMAS – the order in which we do operations.

The B is for brackets – we do them first.

The O is the confusing one, it stands for “Order” which means squared, or cubed or to the power 7 etc: 5² is an example of an order, and means 5 squared, or 5×5 = 25.  Some people use the term Indices instead of Order and so talk of BIDMAS, not BODMAS, but it all means the same.

As we’re talking maths, you’ve probably guessed that the other letters stand for

D – Division

M – Multiply

A – Addition

S – Subtraction

So, going back to our question from above:

2 + 3 x 4

there are no brackets, orders or divisions, so the first thing we do is multiply

2 + 3 x 4 becomes …

2 + 12

So the correct answer is 14.

Remember – BODMAS tells us the order in which we do a sum.

If you want to practice BODMAS  you can find some questions on this worksheet.

Or you could print out and try this BODMAS puzzle.

Or you could try the interactive version of the same puzzle

Here are two great videos that help explain BODMAS.

Boys, in particular, seem to like this one:

… and a little warning, the tune from this one could end up being in your head all day long:

So now you know all about BODMAS, here’s a little puzzle for you to try. Can you arrange all of the digits  from 1 to 9 in each of empty boxes below? You can only use each number once. Remember the rules of BODMAS!

*** UPDATE The puzzle below is now available on pdf for you to download and print: BODMAS Worksheet and also as a ‘draggable’ puzzle for PC, iPad, Whiteboard or whatever: interactive draggable BODMAS puzzle ***