Working Backwards with Inverse Operations - Worksheets, Questions and Revision

20 original exam-style questions - 5 pages of questions with a full mark scheme - free printable PDF.

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11+ · Number and Algebra

EP.M112 Working Backwards with Inverse Operations

GL ASSESSMENT GL-11PLUS-MATHS · Calculators not allowed · about 55 minutes
Total Marks
Name: _______________________________    Date: ____ / ____ / ______
Answer ALL questions. Show all your working.
1
I think of a number. I multiply it by 3 and then add 5. The result is 29. What was my number?
  • A) 8
  • B) 24
  • C) 72
  • D) 9
  • E) 12
(Total for Question 1 is 1 mark)
2
A machine takes a number, subtracts 4, then multiplies the result by 6. The machine shows 60. What number did the machine start with?
  • A) 14
  • B) 56
  • C) 9
  • D) 10
  • E) 64
(Total for Question 2 is 1 mark)
3
Start with a number, add 9, then divide by 3. The result is 7. What was the starting number?
  • A) 12
  • B) 6
  • C) 18
  • D) 3
  • E) 63
(Total for Question 3 is 1 mark)
4
A number is multiplied by 5 and then 15 is taken away. The final result is 10. Which number was it?
  • A) 5
  • B) -5
  • C) 50
  • D) 25
  • E) 2
(Total for Question 4 is 1 mark)
5
I first multiply a number by 2, then I multiply the result by 3, then I add 4. The final result is 34. What was the original number?
  • A) 5
  • B) 6
  • C) 34
  • D) 30
  • E) 10
(Total for Question 5 is 1 mark)
6
A number is squared and then 9 is subtracted to give 16. Which positive whole number could you have started with?
  • A) 5
  • B) -5
  • C) 2
  • D) 7
  • E) 4
(Total for Question 6 is 1 mark)
7
Add 12 to a number, then divide the result by 4. The final answer is 9. What was the original number?
  • A) 24
  • B) 21
  • C) 12
  • D) 36
  • E) 18
(Total for Question 7 is 1 mark)
8
Multiply a number by 10 and then add 3. The final result is 123. What was the number?
  • A) 12
  • B) 120
  • C) 13
  • D) 15
  • E) 9
(Total for Question 8 is 1 mark)
9
You double a number, add 1, then double the result and get 50. What was the original number?
  • A) 12
  • B) 11
  • C) 13
  • D) 6
  • E) 25
(Total for Question 9 is 1 mark)
10
A number is reduced by 30% and then 4 is subtracted to give 31. What was the number at the start?
  • A) 50
  • B) 35
  • C) 45
  • D) 62
  • E) 31
(Total for Question 10 is 1 mark)
11
Start with a number. Add 5, multiply the result by 4, then subtract 6. The final answer is 38. What was the starting number?
  • A) 6
  • B) 7
  • C) 8
  • D) 9
  • E) 5
(Total for Question 11 is 1 mark)
12
A number is divided by 2, then divided by 3, and then 10 is added. The result is 20. What was the original number?
  • A) 60
  • B) 30
  • C) 40
  • D) 90
  • E) 120
(Total for Question 12 is 1 mark)
13
A pupil thinks of a number. He adds 8, halves the result, then multiplies by 5 and gets 55. Work out the original number.
(Total for Question 13 is 2 marks)
14
A number is increased by 15% and then the new amount is divided by 3 to give 46. Find the original number.
(Total for Question 14 is 3 marks)
15
Start with a number. Multiply it by 3, add 7 and then divide the result by 2. The final answer is 20. What was the starting number?
(Total for Question 15 is 3 marks)
16
A number is decreased by 25% and then 10 is added to the result. The final amount is 85. What was the original number?
(Total for Question 16 is 2 marks)
17
A number is multiplied by 2/3 and then 5 is added. The final result is 29. Find the original number.
(Total for Question 17 is 3 marks)
18
I think of a number. I add 4, multiply the result by 3, subtract 9 and then divide by 2. The final answer is 15. Work out the original number.
(Total for Question 18 is 3 marks)
19
A number is squared, then 6 is added and the result is 31. What number was it (positive whole number)?
(Total for Question 19 is 2 marks)
20
A driver halves the miles driven, then adds 12 miles and multiplies the result by 4 to get 200 miles. How many miles were driven at the start?
(Total for Question 20 is 3 marks)
Mark scheme · EP.M112 Working Backwards with Inverse Operations

Question 1

Question 2

Question 3

Question 4

Question 5

Question 6

Question 7

Question 8

Question 9

Question 10

Question 11

Question 12

Question 13

Question 14

Question 15

Question 16

Question 17

Question 18

Question 19

Question 20