Think of a Number Puzzles Worksheet
The trick (Undo the steps): Going forwards: do the steps in order. Going backwards: start from the result and undo each step, last one first. Undo + with −, × with ÷, and doubling with halving.
NameDateTime takenScore ___ / 40
- 1.I thought of a number, added 5 and then doubled it. I got 20. What was my number?
- 2.Magic trick! Think of 5. Double it, add 18, halve it, then take away 5. What number do you get?
- 3.I thought of a number, added 1 and then doubled it. I got 12. What was my number?
- 4.I thought of a number, added 6 and then doubled it. I got 20. What was my number?
- 5.I thought of a number, multiplied it by 5 and added 1. I got 11. What was my number?
- 6.I thought of a number, multiplied it by 3 and added 3. I got 39. What was my number?
- 7.Magic trick! Think of 6. Double it, add 6, halve it, then take away 6. What number do you get?
- 8.I thought of a number, added 6 and then doubled it. I got 26. What was my number?
- 9.Think of 10. Multiply it by 5, then add 4. What number do you end with?
- 10.Magic trick! Think of 19. Double it, add 16, halve it, then take away 19. What number do you get?
- 11.Magic trick! Think of 16. Double it, add 10, halve it, then take away 16. What number do you get?
- 12.I thought of a number, multiplied it by 2 and added 4. I got 18. What was my number?
- 13.Think of 12. Multiply it by 2, then add 4. What number do you end with?
- 14.I thought of a number, multiplied it by 2 and added 3. I got 19. What was my number?
- 15.Magic trick! Think of 8. Double it, add 6, halve it, then take away 8. What number do you get?
- 16.I thought of a number, multiplied it by 3 and added 9. I got 18. What was my number?
- 17.I thought of a number, multiplied it by 3 and added 5. I got 11. What was my number?
- 18.Magic trick! Think of 7. Double it, add 4, halve it, then take away 7. What number do you get?
- 19.Magic trick! Think of 13. Double it, add 10, halve it, then take away 13. What number do you get?
- 20.I thought of a number, added 1 and then doubled it. I got 34. What was my number?
- 21.Magic trick! Think of 5. Double it, add 10, halve it, then take away 5. What number do you get?
- 22.Think of 11. Multiply it by 3, then add 3. What number do you end with?
- 23.I thought of a number, multiplied it by 5 and added 7. I got 27. What was my number?
- 24.I thought of a number, added 4 and then doubled it. I got 14. What was my number?
- 25.Magic trick! Think of 7. Double it, add 16, halve it, then take away 7. What number do you get?
- 26.I thought of a number, added 7 and then doubled it. I got 36. What was my number?
- 27.I thought of a number, added 6 and then doubled it. I got 38. What was my number?
- 28.I thought of a number, added 5 and then doubled it. I got 30. What was my number?
- 29.I thought of a number, multiplied it by 5 and added 7. I got 62. What was my number?
- 30.Magic trick! Think of 2. Double it, add 12, halve it, then take away 2. What number do you get?
- 31.Think of 8. Multiply it by 5, then add 5. What number do you end with?
- 32.Magic trick! Think of 2. Double it, add 10, halve it, then take away 2. What number do you get?
- 33.I thought of a number, multiplied it by 5 and added 1. I got 71. What was my number?
- 34.Magic trick! Think of 3. Double it, add 6, halve it, then take away 3. What number do you get?
- 35.I thought of a number, multiplied it by 2 and added 6. I got 30. What was my number?
- 36.Think of 4. Multiply it by 3, then add 1. What number do you end with?
- 37.Think of 8. Multiply it by 5, then add 1. What number do you end with?
- 38.Magic trick! Think of 12. Double it, add 10, halve it, then take away 12. What number do you get?
- 39.Think of 10. Multiply it by 4, then add 2. What number do you end with?
- 40.I thought of a number, added 6 and then doubled it. I got 48. What was my number?
Answer key
- 5
- 9
- 5
- 4
- 2
- 12
- 3
- 7
- 54
- 8
- 5
- 7
- 28
- 8
- 3
- 3
- 2
- 2
- 5
- 16
- 5
- 36
- 4
- 3
- 8
- 11
- 13
- 10
- 11
- 6
- 45
- 5
- 14
- 3
- 12
- 13
- 41
- 5
- 42
- 18
Free maths tricks lessons, practice and worksheets at talentjr.in/maths-tricks