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Apply the Rules of BIDMAS to Complete the Calculation

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.

'Apply the Rules of BIDMAS to Complete the Calculation' worksheet

Key stage:  KS 2

Curriculum topic:   Verbal Reasoning

Curriculum subtopic:   Complete the Calculation

Difficulty level:  

Worksheet Overview

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

.

boy with laptop

 

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

 

Pssstt!! Here’s a handy hint to help you reach superstar status:

Remember to follow the rules of BIDMAS.


 

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

 

 

 

 

Are you ready for another challenge, number detective?

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! 

 

115 + 78 - 30 =   __ + 4² + 111

 

Let's have a go at another one, number detective!

Below is a calculation where both sides should be equal. 

Can you work out what the missing number is?

 

Remember to follow the rules of BIDMAS!

 

312 + 63 - 110 = __ + 5³ + 100

How are you getting on with this activity, number detective? It can look very challenging but you will find it becomes easier with practice.

Below is a calculation where both sides should be equal. 

Can you find what is the missing number?

 

Remember to follow the rules of BIDMAS! 

 

  88 + 5 x 9 = 21 + 3³ + __

Below is another calculation where both sides should be equal. 

Can you work out what number has been missed out?

 

Remember to follow the rules of BIDMAS!

 

950 - 300 - 300 = __ + 8 x 12

 

girl with question marks

You're halfway through this activity already, number detective!

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!

 

119 - 89 + 200 = __ + 80 x 2

 

boy with magnifying glass

Below is a calculation where both sides should be equal. 

Can you find the missing number?

 

Remember to follow the rules of BIDMAS!

 

95 + 150 ÷ 2 =  __ + 2³ + 65

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

Can you find the mystery number?

 

Remember to follow the rules of BIDMAS!

 

91 + 87 + 41 = 19 + 10 x __

 

You're so nearly there, number detective - don't give up now!

Below is a calculation where both sides should be equal. 

One of the numbers has been removed - can you find what number has been missed out?

 

Remember to follow the rules of BIDMAS!

 

304 - 95 + 17 = __ + 20 x 5

 

 

Only two more questions to go now!

Below is a calculation where both sides should be equal. 

Can you find the missing number?

 

Remember to follow the rules of BIDMAS!

 

215 + 13 x 4 =  110 + 10² + __

 

Hooray, 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!

 

69 + 65 x 2 = 6³ + 23 - __

girl winning race

  • Question 1

Are you ready for another challenge, number detective?

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! 

 

115 + 78 - 30 =   __ + 4² + 111

 

CORRECT ANSWER
36
EDDIE SAYS
How did you find this first question, number detective? If you were tempted to give up now, don't worry - these questions can look very tricky but the secret is to work through them slowly, one step at a time. Remember to work from left to right and use BIDMAS to solve the calculations in this activity. Start on the left side and do the addition first: 115 + 78 = 193. Next, subtract 30 from that to give you a total of 163 on the left-hand side. To solve the right-hand side, do the indices first (that is 4 squared): 4 x 4 = 16. Then, 111 + 16 = 127. Lastly, find the difference between 163 and 127 by doing 163 -127. That wasn't so bad was it?!
  • Question 2

Let's have a go at another one, number detective!

Below is a calculation where both sides should be equal. 

Can you work out what the missing number is?

 

Remember to follow the rules of BIDMAS!

 

312 + 63 - 110 = __ + 5³ + 100

CORRECT ANSWER
40
EDDIE SAYS
Did you find the missing number, detective? The left-hand side of the calculation has a total of 265, which is made by first adding 312 and 63, and then subtracting 110. To work out the right-hand side, you first do 5³, which is 5 x 5 x 5 = 125. Next, you can do addition: 125 + 100 = 225. Lastly, you need to find the difference between 265 and 225 by doing the sum: 265 - 225.
  • Question 3

How are you getting on with this activity, number detective? It can look very challenging but you will find it becomes easier with practice.

Below is a calculation where both sides should be equal. 

Can you find what is the missing number?

 

Remember to follow the rules of BIDMAS! 

 

  88 + 5 x 9 = 21 + 3³ + __

CORRECT ANSWER
85
EDDIE SAYS
You're doing really well! I know that they can be pretty tricky, but just keep calm and work through the calculation one step at a time. Start on the left side by multiplying: 5 x 9 = 45. Next, add 88 to your answer to make the total of 133 on the left side. For the second part, you do 3³ first, which is 3 x 3 x 3 = 27. Then, 27 + 21 = 48. Finally, do 133 - 48. Well done, number detective - let's try another one!
  • Question 4

Below is another calculation where both sides should be equal. 

Can you work out what number has been missed out?

 

Remember to follow the rules of BIDMAS!

 

950 - 300 - 300 = __ + 8 x 12

 

girl with question marks

CORRECT ANSWER
254
EDDIE SAYS
How are you getting on? The left-hand side is quite straight forward this time - they are all subtraction sums, so just work through the list in order, to get the total of 350. To solve the second part of the calculation, first do 8 x 12 = 96, before finally finding the difference between 350 and 96 by doing the sum 350 - 96. You're doing really well with these challenging activities - don't give up!
  • Question 5

You're halfway through this activity already, number detective!

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!

 

119 - 89 + 200 = __ + 80 x 2

 

boy with magnifying glass

CORRECT ANSWER
70
EDDIE SAYS
Are you getting the hang of these yet, number detective? The first side is straight forward and needs you to do a couple of simple subtraction and addition sums to make 230 as the total. To work out the second part, do 80 x 2 = 160. Finally, do 230 - 160 and you're there! Well done, you're halfway through this activity!
  • Question 6

Below is a calculation where both sides should be equal. 

Can you find the missing number?

 

Remember to follow the rules of BIDMAS!

 

95 + 150 ÷ 2 =  __ + 2³ + 65

CORRECT ANSWER
97
EDDIE SAYS
Did you find the number this time, detective? Start with the left-hand side and work through it: division comes before addition in the BIDMAS rule, so that comes first: 150 ÷ 2 = 75. Next, you need to add 95 to this to get the total of 170 on the left-hand side. For the second part of the calculation, do the indices first ( 2 cubed): first, do 2³ = 8. Then, 65 + 8 = 73. Finally, find the difference between 170 and 73 by doing the sum: 170 - 73.
  • Question 7

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

Can you find the mystery number?

 

Remember to follow the rules of BIDMAS!

 

91 + 87 + 41 = 19 + 10 x __

 

CORRECT ANSWER
20
EDDIE SAYS
A tricky one this time, did you manage to work it out? Start on the left side and you can add the numbers in any order because they will give the same answer. This gives you the total 219 for the left. To work out the second part of the calculation, you would normally do the part in brackets first. However, as there is a number missing, you have to do it backwards and with an inverse method. The opposite of adding 19 is subtracting it, so you do 219 - 19 = 200. Then you work out how many tens there are in 200 by doing 200 ÷ 10. This is fantastic work!
  • Question 8

You're so nearly there, number detective - don't give up now!

Below is a calculation where both sides should be equal. 

One of the numbers has been removed - can you find what number has been missed out?

 

Remember to follow the rules of BIDMAS!

 

304 - 95 + 17 = __ + 20 x 5

 

 

CORRECT ANSWER
126
EDDIE SAYS
Did you get this one? The first part of the calculation was a little tricky this time because you needed to add brackets to it. This was so that you knew to do the subtraction before the addition: 304 - 95 = 209. Next, add 17 to that to give 226 as the total on the left hand side. The second part can be solved by doing 20 x 5 = 100. Then 226 - 100.
  • Question 9

Only two more questions to go now!

Below is a calculation where both sides should be equal. 

Can you find the missing number?

 

Remember to follow the rules of BIDMAS!

 

215 + 13 x 4 =  110 + 10² + __

 

CORRECT ANSWER
57
EDDIE SAYS
How are you getting on with these, number detective? Let's work through this one slowly. Take the left side, and the first operation you need to do is multiplication: 13 x 4 = 52. Next, you need to add the number 215 to give the total of 267 on this side. The second part can be worked out by doing the indices first (10 squared): 10 x 10 = 100. Then, 100 + 110 = 210. Lastly, 267 - 210 gives you the answer of 57. Only one question to go!
  • Question 10

Hooray, 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!

 

69 + 65 x 2 = 6³ + 23 - __

girl winning race

CORRECT ANSWER
40
EDDIE SAYS
Did you get this last one, number detective? Don't worry, if not, let's go through it slowly so you can see the different stages. Start with the left side and do the multiplication first: 65 x 2 = 130. Then, add 69 to give a total of 199 on the left-hand side. To solve the second part, first do the indices ( 6 cubed): 6 x 6 x 6 = 216. Then do 216 + 23 = 239. Lastly, find the difference between 239 and 199 by doing 239 - 199. What a legend, you've completed another activity!
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