 # Complete the Calculation Practice 3

In this practice exercise, students will complete a calculation by adding in the missing number so that both sides are equal using BIDMAS, under timed conditions. Key stage:  KS 2

Curriculum topic:  Verbal Reasoning Exam-Style Practice

Curriculum subtopic:  Complete the Calculation

Difficulty level:   ### QUESTION 1 of 10

The following activity is a practice exercise to help you measure your success under timed conditions.

If you are unsure of an answer move on to the next question.  You should come back to questions you found difficult at the end if you have time.

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

Now it's time to begin this practice exercise.  Good luck!

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!

94 + 104 - 88 =   __ + 4³ - 33 76

77

78

79

80

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!

601 + 39 - 340 = __ + 11² + 85

88

90

92

94

96

Below is a calculation where both sides should be equal.

Can you find what the mystery number is?

Remember to follow the rules of BIDMAS!

59 + 11 x 7 = 15 + 8³ - __ 389

390

391

393

395

Below is a calculation where both sides should be equal.

Can you find the mystery number?

Remember to follow the rules of BIDMAS!

770 - 400 - 25 = __ + 9 x 12

237

238

239

240

241

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!

500 - 72 + 50 = __ + 90 x 4 112

114

116

118

120

Below is another calculation where both sides should be equal.

Can you find the missing number?

Remember to follow the rules of BIDMAS!

106 + 130 ÷ 2 =  __ + 12² + 21

3

4

5

6

7

Are you getting the hang of these yet, number detective? Let's try another one.

Below is a calculation where both sides should be equal.

Can you find the mystery number?

Remember to follow the rules of BIDMAS!

77 + 88 - 53 = 32 + 5 x __ 16

10

14

26

18

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

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!

401 - 75 + 24 = __ + 30 x 10

15

50

51

55

60

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!

301 + 14 x 3 =  101 + 9² + __

162

106

101

116

161

Here you are at the very last question - brilliant work, number detective!!

Below is a calculation where both sides should be equal.

For the very last time in this activity, can you find the mystery number?

Remember to follow the rules of BIDMAS!

87 + 51 x 2 = 4³ + 145 - __ 20

21

22

23

24

• Question 1

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!

94 + 104 - 88 =   __ + 4³ - 33 CORRECT ANSWER
79
EDDIE SAYS
How did you get on with this first one, detective? Remember to work from left to right and use BIDMAS to solve the calculations in this activity. Start with the left side, and the first calculation you need to do is addition: 94 + 104 = 198. Next, you need to subtract 88, giving you a total of 110 for the left-hand side. For the second part, you first do the indices (4 cubed): 4³ = 4 x 4 x 4 = 64. Then, you need to do the subtraction: 64 - 33 = 31. Lastly, find the difference between 110 and 31 by doing 110 - 31. It looks tricky, doesn't it, but just take it one step at a time and you're there. Terrific work!
• 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!

601 + 39 - 340 = __ + 11² + 85

CORRECT ANSWER
94
EDDIE SAYS
Did you find the missing number, detective? Once again, just work through it steadily, using BIDMAS and starting with the left side. The first operation to do is therefore addition: 601 + 39 = 640. Next, you need to subtract 340 to give a total of 300 on the left side. For the second part, you first do the indices (11 squared): 11² = 11 x 11 = 121. Then you do 121 + 85 = 206. Lastly, find the difference between 300 and 206 by doing the sum: 300 - 206. There it is - easy really, isn't it?!!
• Question 3

Below is a calculation where both sides should be equal.

Can you find what the mystery number is?

Remember to follow the rules of BIDMAS!

59 + 11 x 7 = 15 + 8³ - __ CORRECT ANSWER
391
EDDIE SAYS
A little bit of a tricky one! Don't panic, though - just work through it step by step! Start with the left side and do the multiplication first: 11 x 7 = 77. Next, add 59 to give the total of 136 for that side. For the second part, do the indices first (8 cubed): 8³ = 8 x 8 x 8 = 512. Then do the sum: 512 + 15 = 527. Lastly, find the difference between 527 and 136 by doing the sum 527 - 136, and you've got your answer! Great stuff, number detective!
• Question 4

Below is a calculation where both sides should be equal.

Can you find the mystery number?

Remember to follow the rules of BIDMAS!

770 - 400 - 25 = __ + 9 x 12

CORRECT ANSWER
237
EDDIE SAYS
How are you getting on? We'll start with the left-hand side - just for a change! All the sums on that side are subtractions so that makes it easy with the order! Once you have done all the subtractions, you should end up with 345 as the total. For the second part, first, you have to do the multiplication: 9 x 12 = 108. All you need to do then is to find the difference between 345 and 108 by doing the sum: 345 - 108. Are you beginning to get to grips with these, number detective?
• 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!

500 - 72 + 50 = __ + 90 x 4 CORRECT ANSWER
118
EDDIE SAYS
Right, let's get to work with this one! It's a bit trickier than some because you have to be careful with the order on the left-hand side of the calculation. Really, this sum should have brackets around the first part (500 - 72) because you must do that before adding on the 50. If that is confusing for you, look carefully at the symbols - it is a minus sign before the 72, so you can't add 72 and 50 together (it is really minus 72 + 50) So, first you must do 500 - 72 and then add the 50 to make a total of 478 on the left-hand side. For the second part, first, do 90 x 4 = 360. Then, find the difference between 478 and 360 by doing the sum: 478 - 360 Oh, what fun. You're halfway done!
• 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!

106 + 130 ÷ 2 =  __ + 12² + 21

CORRECT ANSWER
6
EDDIE SAYS
Did you find the number this time, detective? Starting on the left, the first operation to do is division: 130 ÷ 2 = 65. Next, you can add on 106 to give the total of 171 on that side. To do the right-hand side, you first do the indices (12 squared): 12² = 12 x 12 = 144. Then, do the addition sum: 144 + 21= 165. Lastly, find the difference between 165 and 171 by doing the sum 171 - 165. Easy really!!
• Question 7

Are you getting the hang of these yet, number detective? Let's try another one.

Below is a calculation where both sides should be equal.

Can you find the mystery number?

Remember to follow the rules of BIDMAS!

77 + 88 - 53 = 32 + 5 x __ CORRECT ANSWER
16
EDDIE SAYS
A tricky one this time, did you manage to work it out? Start with the left-hand side and do the addition first: 77 + 88 = 165. Next, subtract 53 from that to get the total of 112 for the left side. For the second part, you would normally do the multiplication first but because there is a number missing there, you will have to work backwards. Instead of adding 32, you subtract 32: so 112 - 32 = 80. Next, instead of multiplying by 5, you divide by 5. So you do 80 ÷ 5, which gives you the answer 16. Well done if you managed to get this one!
• Question 8

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

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!

401 - 75 + 24 = __ + 30 x 10

CORRECT ANSWER
50
EDDIE SAYS
You've put in loads of effort to get this far, number detective. Are you getting the hang of them now? The left-hand side in this question is tricky because we have to imagine that there are brackets around the subtraction sum (401 - 75). This is because we must do this sum first before adding on the 24. So, first we do: 401 - 75 = 326. Next, we add 24 to this to get the total of 350 for that side. For the second part, you do 30 x 10 = 300. Finally, we need to find the difference between 350 and 300 by doing the sum 350 - 300.
• 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!

301 + 14 x 3 =  101 + 9² + __

CORRECT ANSWER
161
EDDIE SAYS
Did you have to put on your thinking cap for this one? Start on the left with the multiplication sum: 14 x 3 = 42. Next, add 301 to give the total of 343 on the left-hand side. For the second part, to find the missing number, you first need to do the indices (9 squared): 9² = 9 x 9 = 81. Then, the addition sum: 81 + 101 = 182. Lastly, you need to find the difference between 343 and 182 by doing the sum: 343 - 182, which gives us 161. Great work, detective. Now, on to that final question!
• Question 10

Here you are at the very last question - brilliant work, number detective!!

Below is a calculation where both sides should be equal.

For the very last time in this activity, can you find the mystery number?

Remember to follow the rules of BIDMAS!

87 + 51 x 2 = 4³ + 145 - __ CORRECT ANSWER
20
EDDIE SAYS
For the last time in this activity, let's work through step by step. For the left hand side, do the multiplication first: 51 x 2 = 102. Next, add on 87 to give the total of 189 on the left hand side. For the second part, you first have to do 4³= 64. Then, 145 + 64 = 209. Lastly, find the difference between 189 and 209 by doing the sum 209 - 189, and you've done it! Guess what, detective, you've completed this activity and collected all the numbers. Hopefully, you are feeling more confident with this type of question now. Terrific work!
---- 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.

Start your £1 trial