# 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!

Welcome to the first of these worksheets on Completing the Calculation. Are you ready to begin, 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?

(32 ÷ 2) + 12 = (4 x 6) + __

Ready for another one, number detective?

Below is a calculation where both sides should be equal.

Can you work out the missing number?

(55 ÷ 5) + 41 =   (7 x 6) + __

Right then, number detective, let's try another one!

Below is a calculation where both sides should be equal.

Can you find the missing number?

(12 x 6) + 44 = (50 x 3) - __

Let's have another go.

Below is a calculation where both sides should be equal.

Can you work out what number has been missed out, number detective?

(50 ÷ 2) + 77 = (16 x 10) - __

Below is another calculation where both sides should be equal.

Can you work out what number has been missed out?

(7 x 7) + 42 = (38 ÷ 2) + __

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

Below is a calculation where both sides should be equal.

Can you find out what the mystery number is?

(54 ÷ 6) x 5 = (109 + 73) - __

Here's another juicy calculation to get your teeth into!

Below is a calculation where both sides should be equal.

Can you use your detecting skills to work out the missing number?

(171 + 85) - 22 = (80 x 3) + __

You're doing really well, number detective.

Below is a calculation where both sides should be equal.

Can you work out what the missing number is?

(30 x 3) + 99 = (222 + 44) - __

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?

(11 x 7) + 195 =  (90 x 4) - __

Now, don't get over-excited but this is the last question!

Below is a calculation where both sides should be equal.

Can you work out what number is missing?

(20 x 10) + 154 = (50 x 6) + __

• Question 1

Welcome to the first of these worksheets on Completing the Calculation. Are you ready to begin, 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?

(32 ÷ 2) + 12 = (4 x 6) + __

4
EDDIE SAYS
Welcome detective! For the questions in this activity, you need to work out the left-hand side first, followed by the right-hand side. Starting on the left-hand side, you use the rules of BIDMAS to sort out the order of the calculations. Start with B (brackets): 32 ÷ 2 = 16. Next, you need to add 12 and this gives you a total of 28 for the left-hand side. Now, all you have to to do is make the right-hand side also equal 28. To do this, you do the brackets first: 4 x 6 = 24. Finally, you have to work out what to add to 24 to make the number 28. Here's the sum you do: 28 - 24 = 4. So, your mystery number is 4. There's a lot to do in these questions but don't panic, just work through it slowly, one bit at a time.
• Question 2

Ready for another one, number detective?

Below is a calculation where both sides should be equal.

Can you work out the missing number?

(55 ÷ 5) + 41 =   (7 x 6) + __

10
EDDIE SAYS
OK, let's take it slowly. Do the calculation on the left first: you need to do the brackets first so 55 ÷ 5 = 11. Then add on 41 to make the total 52. Now, you need to make the total of the right-hand side also equal 52. Start with the brackets: 7 x 6 = 42. You now have to find out how much you need to add to 42 to reach 52. This is the sum 52 - 42 which gives you the answer of 10! Fantastic!
• Question 3

Right then, number detective, let's try another one!

Below is a calculation where both sides should be equal.

Can you find the missing number?

(12 x 6) + 44 = (50 x 3) - __

34
EDDIE SAYS
Remember what you have to do? Start with the left-hand side of the calculation and work out the brackets first: 12 x 6 = 72. Then add on 44 to make 116. For the calculation on the right, you do 50 x 3 = 150. You now need to work out what you need to subtract from 150 to make 116. The sum for this is 150 - 116, which gives you the answer of 34. Just take it one step at a time and you'll get there.
• Question 4

Let's have another go.

Below is a calculation where both sides should be equal.

Can you work out what number has been missed out, number detective?

(50 ÷ 2) + 77 = (16 x 10) - __

58
EDDIE SAYS
What a lot of numbers! Start with the calculation on the left and do the brackets first: 50 ÷ 2 = 25. Then add on 77 to make the total of 102. Now, you have to make the right hand side also equal 102. Start with the brackets: 16 x 10 = 160. You now need to work out what to subtract from 160 to make 102: 160 - 102 = 58. There's your mystery number!
• Question 5

Below is another calculation where both sides should be equal.

Can you work out what number has been missed out?

(7 x 7) + 42 = (38 ÷ 2) + __

72
EDDIE SAYS
Are you getting the hang of it? First, work out the calculation on the left, doing the brackets first: 7 x 7 = 49. Then add on 42 to make 91. For the calculation on the right, you do 38 ÷ 2 = 19. Now, you have to find the difference between 91 and 19. So you do 91 - 19, which gives you the mystery number of 72.
• Question 6

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

Below is a calculation where both sides should be equal.

Can you find out what the mystery number is?

(54 ÷ 6) x 5 = (109 + 73) - __

137
EDDIE SAYS
How did you do with this one? For the calculation on the left, you do the brackets first: 54 ÷ 6 = 9. Then, multiply 9 by 5 to total 45. For the calculation on the right, you do 109 + 73 = 182. Now, you need to find the difference between 182 and 45, so you do 182 - 45, which will give you the answer 137. Remember, just take it stage by stage, number detective.
• Question 7

Here's another juicy calculation to get your teeth into!

Below is a calculation where both sides should be equal.

Can you use your detecting skills to work out the missing number?

(171 + 85) - 22 = (80 x 3) + __

6
EDDIE SAYS
How did you find this question, detective? Don't panic if you get big numbers in the calculation - just treat it the same way as the other ones and take it one step at a time. So, we start with the brackets on the left-hand side: 171 + 85 = 256. Then, subtract 22 to total 234. For the calculation on the right, do 80 x 3 = 240. All you have to do now is work out what to subtract from 240 to reach 234, which you can do with the sum 240 - 234 = 6. Phew, another one ticked off!
• Question 8

You're doing really well, number detective.

Below is a calculation where both sides should be equal.

Can you work out what the missing number is?

(30 x 3) + 99 = (222 + 44) - __

77
EDDIE SAYS
OK, let's go through it slowly. For the calculation on the left, you do the brackets first: 30 x 3 = 90. Then, 90 + 99 = 189. For the calculation on the right, you do 222 + 44 = 266. Finally, you need to make the two sides equal by finding out what you need to subtract from 266 to make 189. So, we must find the difference: 266 - 189 = 77. Nice work, detective!
• 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?

(11 x 7) + 195 =  (90 x 4) - __

88
EDDIE SAYS
Did you find the missing number, detective? In case you're finding it hard, let's go through all the steps slowly. For the calculation on the left, do the brackets first: 11 x 7 = 77. Then add on 195, to total the massive 272. Now, you have to make the right-hand side also equal 272. Start with the brackets 90 x 4 = 360. Finally, you need to find the difference between 360 and 272 by doing the sum 360 - 272 = 88. There you have it - easy isn't it?!!
• Question 10

Now, don't get over-excited but this is the last question!

Below is a calculation where both sides should be equal.

Can you work out what number is missing?

(20 x 10) + 154 = (50 x 6) + __

54
EDDIE SAYS
OK, let's go. For the calculation on the left, you do 20 x 10 = 200. Then add on 154, to total 354. For the calculation on the right, you do 50 x 6 = 300. Then, find the difference between 354 and 300 by doing 354 - 300, which gives the answer 54! Phew! There were quite a few calculations in this activity, but you've done really well and helped us to find the missing numbers! Hopefully, you've had some fun too, number detective.
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