# Solve the Calculation Using BIDMAS

In this worksheet, students will complete a calculation by adding in the missing number so that both sides are equal. They will need to follow the rules of BIDMAS. It will strengthen their number skills.

Key stage:  KS 2

Curriculum topic:   Verbal Reasoning

Curriculum subtopic:   Complete the Calculation

Difficulty level:

### QUESTION 1 of 10

Calling all number detectives!

Look at this symbol:

We know it is the equals sign but what does it actually mean?

It means the same as and doesn’t just mean the answer.

Look at the following calculation:

7 + 5 x 3 = 10 x 2+ ( __ )

Both sides of the calculation must be equal.

We need to work out the answer to the left side of the calculation before we can work out the mystery number on the right side of the calculation.

We must follow the rules of BIDMAS (or BODMAS) in these calculations.

When you complete a calculation using BIDMAS, you answer anything in brackets first, then any indices (squared and cubed numbers),  then the division and multiplication parts, followed by the addition and subtraction parts.

Following the rules of BIDMAS, we must calculate 5 x 3 first and then add 7. This gives us 22.

So the answer on the right must equal 22. 10 x 2 is 20 so the mystery number must be 2 to make a total of 22.

7 + (5 x 3) = (10 x 2) + 2

Remember to follow the rules of BIDMAS.

It’s now your turn to complete the calculation! Good luck!

Below is a calculation where both sides should be equal.

However, one of the numbers has been taken away by the cheeky number burglar! Can you work out what it is?

(135 + 81) - 101 = (103 x 3) - __

Are you ready for another one, number detective?

Below is a calculation where both sides should be equal.

Can you work out what is number is missing?

(12 x 7) x 2 =   __ + (200 ÷ 4)

Let's have a go at another one.

Below is a calculation where both sides should be equal.

Can you work out what the missing number is?

4 x (8 x 6) = (350 - 120) - __

Here's another exciting question to tackle, number detective!

Below is a calculation where both sides should be equal.

Can you use your detecting skills to work out what the mystery number is?

298 + (500 ÷ 100) = (110 x 3) - __

Below is a calculation where both sides should be equal.

Can you work out what the mystery number is?

(50 x 5) + 34 = (99 x 3) - __

Below is yet another calculation where both sides should be equal.

Can you find the missing number?

2 x (11 x 11) = (600 ÷ 2) - __

Keep going, number detective, you're doing really well!

Below is a calculation where both sides should be equal.

Can you work out what the missing number is?

2 x (55 x 2) = __ + (90 ÷ 5)

Below is yet another calculation where both sides should be equal!

Can you find the missing number?

245 + (900 ÷ 3) = __ + (7 x 7)

Only two more questions to go, number detective!

Below is a calculation where both sides should be equal.

Can you find what number has been missed out?

(808 - 80) - 87 = __ + (60 x 6)

The last question - yippee!

Below is a calculation where both sides should be equal.

Can you find the mystery number?

(500 x 2) - 200 = __ + (350 x 2)

• Question 1

Below is a calculation where both sides should be equal.

However, one of the numbers has been taken away by the cheeky number burglar! Can you work out what it is?

(135 + 81) - 101 = (103 x 3) - __

194
EDDIE SAYS
Hello detective! Remember that we need to work from left to right to solve the calculation and we must solve the part in brackets first. So, first, we take the brackets on the left-hand side: 135 + 81 = 216. Then, we must subtract 101 to total 115. We now need to make the right-hand side also equal 115. We start with the brackets: 103 x 3 = 309. Now, all you need to do is find the difference between 309 and 115 by doing 309 - 115, which gives us the answer 194. Excellent work!
• Question 2

Are you ready for another one, number detective?

Below is a calculation where both sides should be equal.

Can you work out what is number is missing?

(12 x 7) x 2 =   __ + (200 ÷ 4)

118
EDDIE SAYS
How did you get on with this one? For the calculation on the left, you work out the brackets first: 12 x 7 = 84. Then, multiply 84 by 2 to total 168. Now, we need to make the right-hand side also equal 168. We start with the brackets: 200 ÷ 4 = 50. Then, we have to find the difference between 168 and 50 by doing 168 - 50. This gives us our mystery number of 118.
• Question 3

Let's have a go at another one.

Below is a calculation where both sides should be equal.

Can you work out what the missing number is?

4 x (8 x 6) = (350 - 120) - __

38
EDDIE SAYS
OK, let's take it slowly, one step at a time. For the calculation on the left, you still start with the brackets, even though they are not the first thing in the sum: 8 x 6 = 48. Then, you do 48 x 4 = 192. For the calculation on the right, you start with the brackets: 350 - 120 = 230. Finally, you need to find the difference between 230 and 192 which means doing the sum: 230 - 192. Are you getting the hang of these yet, number detective?
• Question 4

Here's another exciting question to tackle, number detective!

Below is a calculation where both sides should be equal.

Can you use your detecting skills to work out what the mystery number is?

298 + (500 ÷ 100) = (110 x 3) - __

27
EDDIE SAYS
Numbers, numbers, numbers! Don't panic, let's just work through it one step at a time. For the calculation on the left, you still start with the brackets, even though it is not the first part of the sum: 500 ÷ 100 = 5. Then, do 298 + 5 = 303. Next, do the calculation on the right, starting with the brackets: 110 x 3 = 330. Now all you have to do is find the difference between 330 and 303 by doing 330 - 303. Did you work all that out, number detective?
• Question 5

Below is a calculation where both sides should be equal.

Can you work out what the mystery number is?

(50 x 5) + 34 = (99 x 3) - __

13
EDDIE SAYS
How did you get on with this one? First, work out the brackets on the left-hand side: 50 x 5 = 250. Then, add on 34 to make 284. For the calculation on the right, do 99 x 3 = 297. Finally, find the difference between 297 and 284 by doing 297 - 284 and you're there! Terrific detecting skills if you got this one right!
• Question 6

Below is yet another calculation where both sides should be equal.

Can you find the missing number?

2 x (11 x 11) = (600 ÷ 2) - __

58
EDDIE SAYS
Let's do this step by step. Start off by doing the brackets on the left-hand side: 11 x 11 = 121. Multiply this by 2 to get 242. Next, do the brackets on the right-hand side: 600 ÷ 2 = 300. Finally, find the difference between 300 and 242 by doing 300 - 242, which gives you the mystery number of 58.
• Question 7

Keep going, number detective, you're doing really well!

Below is a calculation where both sides should be equal.

Can you work out what the missing number is?

2 x (55 x 2) = __ + (90 ÷ 5)

202
EDDIE SAYS
How did you find this question, detective? For the calculation on the left do the brackets first, even though they are not the first thing in the sum: 55 x 2 = 110. Then, 110 x 2 = 220. Next, do the calculation on the right: 90 ÷ 5 = 18. Finally, find the difference between 220 and 18 by doing 220 - 18, which gives you the answer 202. Great work!
• Question 8

Below is yet another calculation where both sides should be equal!

Can you find the missing number?

245 + (900 ÷ 3) = __ + (7 x 7)

496
EDDIE SAYS
Did you work out the missing number? This looks a tricky one with all these big numbers, but don't panic!! Start off by doing 900 ÷ 3 = 300. Then, add on 245 to make 545. After that, work out the brackets on the right side: 7 x 7 = 49. Finally, find the difference between 545 and 49 by doing the sum 545 - 49 = 496. And you're there - yippee!!
• Question 9

Only two more questions to go, number detective!

Below is a calculation where both sides should be equal.

Can you find what number has been missed out?

(808 - 80) - 87 = __ + (60 x 6)

281
EDDIE SAYS
This one involves some complicated sums so it really tests your subtraction skills. How did you get on with it? First, do the brackets on the left-hand side: 808 - 80 = 728. Then, 728 - 87 = 641. To work out the calculation on the left, do the brackets: 60 x 6 = 360. Finally, find the difference by doing 641 - 360, which should give you the mystery number of 281. Great, one more question to go!
• Question 10

The last question - yippee!

Below is a calculation where both sides should be equal.

Can you find the mystery number?

(500 x 2) - 200 = __ + (350 x 2)

100
EDDIE SAYS
Did you get this final one OK, number detective? For the calculation on the left, you do 500 x 2 = 1000. Then, 1000 - 200 = 800. For the calculation on the right, do 350 x 2 = 700. Then 800 - 700 = 100. Thanks for all your help completing the calculations in this activity! Hopefully, you have found them easier with practice and enjoyed the challenge!
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