# Solve the Calculations 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!

Welcome aboard, number detective. Here is another juicy activity to get your teeth into!

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!

44 + 12 x 7 = __ + 10 x 11

Are you ready to try another one, 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!

77 + 50 ÷ 2 = __ + 6 x 8

Let's try another one, number detective.

Below is a calculation where both sides should be equal.

Can you work out what number is missing?

Remember to follow the rules of BIDMAS!

54 x 10 - 37 = 600 - 40 - __

Below is another calculation where both sides should be equal.

Can you find what number has been missed out?

Remember to follow the rules of BIDMAS!

200 - 27 - 41 = 33 ÷ 3 x __

You're halfway through already, 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!

87 + 22 + 41 = 50 x 4 - __

Below is another calculation where both sides should be equal.

Can you find the mystery number?

Remember to follow the rules of BIDMAS!

150 + 15 x 3 = 300 - 250 + __

Keep going, number detective, you're nearly there!

Below is a calculation where both sides should be equal.

Can you find what number has been missed out?

Remember to follow the rules of BIDMAS!

95 ÷ 5 x 2 = 105 - 43 - __

On we go to the next challenge, 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!

500 + 500 - 300 = 500 + 400 - __

Only two more questions to go now!

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!

91 + 34 - 25 = 5 x 10 x __

Well done, number detective, you have reached the final question in this activity! Hooray!!

Below is a calculation where both sides should be equal.

Can you find what number has been missed out?

Remember to follow the rules of BIDMAS!

109 + 90 - 51 = 12 x 4 + __

• Question 1

Welcome aboard, number detective. Here is another juicy activity to get your teeth into!

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!

44 + 12 x 7 = __ + 10 x 11

18
EDDIE SAYS
Welcome detective! Did you remember to use BIDMAS to solve this calculation? You need to start with the left-hand side - there are no brackets, indices or division, so the first operation is MULTIPLICATION: 12 x 7 = 84. Next, you need to add 44 to make the total 128. To make the same total for the right side, you do the multiplication first: 10 x 11 = 110, and finally, you have to find the difference between 128 and 110 by doing the sum 128 - 110. This gives you 18 as your mystery number - yippee!
• Question 2

Are you ready to try another one, 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!

77 + 50 ÷ 2 = __ + 6 x 8

54
EDDIE SAYS
Did you find the missing number, detective? Once again, you need to start with the left-hand side and work through the order of BIDMAS. There are no brackets or indices, so the first operation to do is DIVISION: 50 ÷ 2 = 25. Next, you need to add 77 to make the total of 102. To find the missing number for the right-hand side, you do the multiplication first: 6 x 8 = 48 and then find the difference between 102 and 48 by doing the sum 102 - 48, which gives you the answer 54. Just work slowly and carefully through each step and it makes it much easier.
• Question 3

Let's try another one, number detective.

Below is a calculation where both sides should be equal.

Can you work out what number is missing?

Remember to follow the rules of BIDMAS!

54 x 10 - 37 = 600 - 40 - __

57
EDDIE SAYS
Are you getting the hang of these yet? Start with the left-hand side and work through the operations - there are no brackets, indices or division, so the first operation is MULTIPLICATION: 54 x 10 = 540. Next, you need to subtract 37 from it, giving the total of 503. To work out the right-hand side, you need to subtract 40 from 600, which gives you 560. Finally, you need to find the difference between 560 and 503 by doing the sum 560 - 503. Your answer is 57. Did you get that one OK, number detective?
• Question 4

Below is another calculation where both sides should be equal.

Can you find what number has been missed out?

Remember to follow the rules of BIDMAS!

200 - 27 - 41 = 33 ÷ 3 x __

12
EDDIE SAYS
Numbers, numbers, numbers! Start with the left hand side and work through all those subtractions sums to get the number 132. To find the missing number on the right, you first do 33 ÷ 3 = 11. Then, you have to find how many elevens there are in 132, which is the sum: 132 ÷ 11. This gives you the answer 12. How did you find this one, number detective?
• Question 5

You're halfway through already, 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!

87 + 22 + 41 = 50 x 4 - __

50
EDDIE SAYS
Let's go through it in stages. First, take the left-hand side and work through all those addition sums to make the number 150. To get the same total on the right, you do 50 x 4 = 200. Finally, you have to find the difference between 200 and 150 by doing the sum 200 - 150. Oh what fun, you're halfway done!
• Question 6

Below is another calculation where both sides should be equal.

Can you find the mystery number?

Remember to follow the rules of BIDMAS!

150 + 15 x 3 = 300 - 250 + __

145
EDDIE SAYS
Did you get this one, number detective? On the left-hand side, you do the multiplication first: 15 x 3 = 45 and then add 150 to it to make a total of 195. To get the same number on the right side, you need to do 300 - 250 to get 50. Finally, you need to subtract 50 from 195, leaving you with the mystery number of 145. Great stuff!
• Question 7

Keep going, number detective, you're nearly there!

Below is a calculation where both sides should be equal.

Can you find what number has been missed out?

Remember to follow the rules of BIDMAS!

95 ÷ 5 x 2 = 105 - 43 - __

24
EDDIE SAYS
How did you do, detective! To solve the left-hand side, you need to work through the order of BIDMAS. There are no brackets or indices, so the first operation you need to do is DIVISION: 95 ÷ 5 = 19. Next, you need to do multiplication: 19 x 2 = 38. To work out the answer to the right-hand side, you need to do 105 - 43 = 62. Finally, you find the difference between 62 and 38 by doing the sum 62 - 38. This gives us our missing number of 24. Terrific work, number detective!
• Question 8

On we go to the next challenge, 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!

500 + 500 - 300 = 500 + 400 - __

200
EDDIE SAYS
Did you find the missing number? It is actually very straight forward this time. Start with the left-hand side, and add the first two numbers to make 1,000. Subtract 300 from that and you get the total of 700 for the left side. To get the same total on the right side, you do 500 + 400 = 900 and, finally, you need to find the difference between 900 and 700 by doing 900 - 700. Did you find this one OK, number detective?
• Question 9

Only two more questions to go now!

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!

91 + 34 - 25 = 5 x 10 x __

2
EDDIE SAYS
Hopefully, you didn't find this one too hard, number detective. First, work out the answer to the left side of the sum by doing 91 + 34 = 125. Next, subtract 25 which gives you 100. To do the right-hand side, you do 5 x 10 = 50 and finally, you need to count how many fifties there are in 100 by doing 100 ÷ 50 = 2. Great calculating!
• Question 10

Well done, number detective, you have reached the final question in this activity! Hooray!!

Below is a calculation where both sides should be equal.

Can you find what number has been missed out?

Remember to follow the rules of BIDMAS!

109 + 90 - 51 = 12 x 4 + __

100
EDDIE SAYS
Well, how did you do with this last question, number detective? Hopefully, you are feeling more confident with these questions now. Remember to always start with the left side and work through the order of operations using BIDMAS. With this question, the first thing is to do 109 + 90 = 199. Next, you need to subtract 51: 199 - 51 = 148. To find the missing number on the right-hand side, you do 12 x 4 = 48 and, finally, 148 - 48 to give you 100! Hey, I'll tell you something pretty neat, this activity is now complete!
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