Albert Teen YOU ARE LEARNING:  BIDMAS  # BIDMAS ### BIDMAS

When a calculation involves multiple operations, we must decide which order to perform our operations

The order we carry out calculations like $+$ , $-$ , $\times$ or $\div$ affects the final answer. What is the correct order to carry them out? 1

BIDMAS tells us the order of operations

Brackets come first, while addition and subtraction come last. 2

This is true of all calculations. 3

Would you do multiplication before or after addition?  Let's try this example together: $6 + 5 \times 3$

1

We will walk through this step by step

Don't forget that BIDMAS gives us the order of operations 2

We have two operations here: addition $+$ and multiplication $\times$ Using BIDMAS, which one do we calculate first?  3

What is $5 \times 3$?  4

Now we use the value we've just found

The calculation is now $6 + 15$ 5

What is $6 + 15$?  6

Good work!

The final answer is $21$ 1

Division and Multiplication are equal (as they are opposite operations). If they appear in the same question, go from left to right.

This also applies to Addition and Subtraction.

2

There is one tricky thing about BIDMAS when it comes to addition and subtraction.

When it is just addition and subtraction, we must work from left to right.

3

The correct answer is found by working from left to right. What is $24-10+4$?  4

But what happens if we do the addition first?

We know that $10+4=14$. 5

What is the final answer now?  6

It's not possible for both of these answers to be correct!

Remember when it is just addition and subtraction, work from left to right. Now let's try working out this one: $7^2 - 3 \times 8 + 2$

1

This one has a few more operations

And we will walk through it step by step 2

We have four operations here

Indices $7^2$ subtraction $7^2-3$, multiplication $3 \times 8$,
addition $8+2$ 3

Which operation do we do first?  4

So what is $7^2$?  5

Multiplication is the next step. What is $3\times8$?  6

Let's put these into our calculation

It now looks like $49-24+2$ 7

What happens next?

Addition and subtraction are equal in order, so we perform from left to right. 8

What is $49-24+2$?  9

Nice! 👍

The final answer is $27$ Here is a quick test before we move on.

What is $2 + 3 \times 4$? And how about $5 \times 3^2$? This is a slightly harder one!

1

This exercise will use all of the operations

Let's walk through it step by step.... 2

Tackle the brackets in the numerator first

B is the first letter in BIDMAS 3

Which operation do we do first?  4

What is $8 \times 2$?  5

Subtract $4$ from $16$

$16-4=12$ 6

Now we can tackle the set of brackets in the denominator. Do the indices first

$1^2=1$ 7

Finish the calculation in the bracket by adding the numbers together

$1+3=4$ 8

Divide the numerator by the denominator

$\dfrac{12}{4}=3$ 9

Nice!

The final answer is $3$ Find $\dfrac{(7-2^2)}{(4^2-15)}$.

Feel free to take your time working this one out. You may need to write your workings down. 1

Summary! BIDMAS tells us the order of operations

Brackets come first, while addition and subtraction come last. 2

If we only have addition and subtraction we must work from left to right.

Do the calculation as if you were reading it 