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?

Remember to follow the rules of BIDMAS!

62 + 7 x 8 = __ + 110 ÷ 5

Ready for another one, number detective?

Below is a calculation where both sides should be equal.

Can you work out what the mystery number is?

Remember to follow the rules of BIDMAS!

84 ÷ 7 x 11 = 232 - 105 + __

Here we go again, number detective!

Below is a calculation where both sides should be equal.

Can you find the missing number?

Remember to follow the rules of BIDMAS!

102 + 8 x 8 = 55 x 4 - __

You're doing a great job with these, number detective!

Below is a calculation where both sides should be equal.

Can you work out the missing number?

Remember to follow the rules of BIDMAS!

12 x 8 x 2 = __ + 300 ÷ 2

Below is a calculation where both sides should be equal.

Can you use your detecting skills to find the missing number?

Remember to follow the rules of BIDMAS!

350 - 150 - 74 = 12 x 7 + __

Below is another calculation where both sides should be equal.

Can you find the missing number?

Remember to follow the rules of BIDMAS!

110 + 11 x 11 = __ + 30 x 7

You're doing really well, number detective - don't give up!

Below is a calculation where both sides should be equal.

Can you find out what number has been missed out?

Remember to follow the rules of BIDMAS!

18 x 2 ÷ 4 = 180 ÷ 2 ÷ __

Here's another challenge for you, number detective!

Below is a calculation where both sides should be equal.

Can you find out what the missing number is?

Remember to follow the rules of BIDMAS!

150 + 50 x 6 = 400 + 700 - __

Only two more questions to go, number detective!

Below is a calculation where both sides should be equal.

Can you find the missing number?

Remember to follow the rules of BIDMAS!

167 - 43 - 36 = 22 x 2 x __

You've reached the final question, number detective!

Below is a calculation where both sides should be equal.

Can you find the mystery number?

Remember to follow the rules of BIDMAS!

9 x 8 + 110 = __ + 40 x 3

• 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?

Remember to follow the rules of BIDMAS!

62 + 7 x 8 = __ + 110 ÷ 5

96
EDDIE SAYS
Greetings detective! Remember we need to work from left to right to solve the calculation and have to follow the rules of BIDMAS. You need to start with the left-hand side and work through the order of operations using BIDMAS. There are no brackets, indices or division on the left-hand side so the first thing we need to do is MULTIPLY: 7 x 8 = 56. Now, we need to add 62 to 56 to get 118. Next, we need to make the right-hand side also equal 118. First, we need to DIVIDE: 110 ÷ 5 = 22. Finally, we have to find the difference between 118 and 22, which means doing the sum 118 - 22 = 96. Great work, detective!
• Question 2

Ready for another one, number detective?

Below is a calculation where both sides should be equal.

Can you work out what the mystery number is?

Remember to follow the rules of BIDMAS!

84 ÷ 7 x 11 = 232 - 105 + __

5
EDDIE SAYS
Did you work this one out? Start with the left-hand side and work through the BIDMAS order of operations. There are no brackets or indices, so the first operation to do on the left-hand side is DIVISION: 84 ÷ 7 = 12. Now, you have to multiply this by 11 to get 132. To find the same total on the right, we need to do 232 + 105 = 127. Finally, you have to find the difference between 127 and 132, which gives 5 as the mystery number.
• Question 3

Here we go again, number detective!

Below is a calculation where both sides should be equal.

Can you find the missing number?

Remember to follow the rules of BIDMAS!

102 + 8 x 8 = 55 x 4 - __

54
EDDIE SAYS
Are you getting the hang of these yet, number detective? Working from left to right, and following the order of BIDMAS, the first calculation is MULTIPLICATION: 8 x 8 - 64. Then, we have to add 102 to make the total of 166. To get the same total for the part on the right, you do 55 x 4 = 220 and finally, do 220 - 166, which gives you 54.
• Question 4

You're doing a great job with these, number detective!

Below is a calculation where both sides should be equal.

Can you work out the missing number?

Remember to follow the rules of BIDMAS!

12 x 8 x 2 = __ + 300 ÷ 2

42
EDDIE SAYS
Numbers, numbers, numbers! Remember, you start on the left and follow the order of BIDMAS. There are no brackets, indices or division, so the first thing to do is MULTIPLICATION: 12 x 8 = 96 x 2 = 192. To get the same amount on the right, you do 300 ÷ 2 = 150. Finally, you do 192 - 150 = 42.
• Question 5

Below is a calculation where both sides should be equal.

Can you use your detecting skills to find the missing number?

Remember to follow the rules of BIDMAS!

350 - 150 - 74 = 12 x 7 + __

42
EDDIE SAYS
Good work detective! Start with the left side and work through all those subtractions to get 126. To get the same total for the part on the right, you do 12 x 7 = 84 and finally, 126 - 84, which equals 42.
• Question 6

Below is another calculation where both sides should be equal.

Can you find the missing number?

Remember to follow the rules of BIDMAS!

110 + 11 x 11 = __ + 30 x 7

21
EDDIE SAYS
Are you getting the hang of these yet, number detective? The part of the calculation on the left has no brackets, indices or division, so the first operation to do is MULTIPLICATION: 11 x 11 = 121. Then, we need to add 110 making a total of 231. To get the same number on the right, you do 30 x 7 = 210. Finally, we need to do the sum 231 - 210 to get the answer 21. Great calculating skills!
• Question 7

You're doing really well, number detective - don't give up!

Below is a calculation where both sides should be equal.

Can you find out what number has been missed out?

Remember to follow the rules of BIDMAS!

18 x 2 ÷ 4 = 180 ÷ 2 ÷ __

10
EDDIE SAYS
Are you getting the hang of using BIDMAS? This one is a bit more tricky because we actually have to add brackets before we can work it out. The left-hand side means that we need to divide the total that is made when we multiply 18 and 2 together. To show this in a sum, we add brackets so that it becomes (18 x 2) ÷ 4. This means that we do the brackets, first which gives us 18 x 2 = 36 and then divide that by 4, giving us the answer of 9. To reach a total of 9 for the part on the right, you do 180 ÷ 2 = 90. Finally, you need to work out how many nines there are in 90 by doing 90 ÷ 9. This gives us our mystery number of 10. Yippee!!
• Question 8

Here's another challenge for you, number detective!

Below is a calculation where both sides should be equal.

Can you find out what the missing number is?

Remember to follow the rules of BIDMAS!

150 + 50 x 6 = 400 + 700 - __

650
EDDIE SAYS
Did you find out what the missing number is? Start with the left side and follow the order of BIDMAS. There are no brackets, indices or division, so the first operation is MULTIPLICATION: 50 x 6 = 300. Then, we have to add 150 to give us a total of 450. To get the same answer on the right side, you do 400 + 700 = 1100. Finally, find the difference between 1100 and 450 by doing 1100 - 450, which gives us 650!!
• Question 9

Only two more questions to go, number detective!

Below is a calculation where both sides should be equal.

Can you find the missing number?

Remember to follow the rules of BIDMAS!

167 - 43 - 36 = 22 x 2 x __

2
EDDIE SAYS
Right, let's go through this in order. First, do the left-hand side, working through all those subtractions and you arrive at the number 88. To solve the part on the right, you do 22 x 2 = 44. Finally, you have to find what you need to multiply 44 by to get 88 which can be solved by doing 88 ÷ 44. Great, only one question to go!
• Question 10

You've reached the final question, number detective!

Below is a calculation where both sides should be equal.

Can you find the mystery number?

Remember to follow the rules of BIDMAS!

9 x 8 + 110 = __ + 40 x 3

62
EDDIE SAYS
How did you do with this last one, number detective? The first operation to do on the left side is multiplication: 9 x 8 = 72. Then, you have to add on 110 = 182. To make the same number on the right, you do 40 x 3 = 120. Finally, work out 182 - 120 to find the missing number of 62. You've been an amazing help to us by finding so many numbers, detective. We hope to see you soon on another awesome activity!
---- OR ----

Sign up for a £1 trial so you can track and measure your child's progress on this activity.

What is EdPlace?

We're your National Curriculum aligned online education content provider helping each child succeed in English, maths and science from year 1 to GCSE. With an EdPlace account you’ll be able to track and measure progress, helping each child achieve their best. We build confidence and attainment by personalising each child’s learning at a level that suits them.

Get started