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 7 and then doubled it. I got 54. What was my number?
- 2.Think of 9. Multiply it by 3, then add 1. What number do you end with?
- 3.Magic trick! Think of 9. Double it, add 18, halve it, then take away 9. What number do you get?
- 4.Magic trick! Think of 16. Double it, add 14, halve it, then take away 16. What number do you get?
- 5.Magic trick! Think of 19. Double it, add 10, halve it, then take away 19. What number do you get?
- 6.I thought of a number, added 3 and then doubled it. I got 36. What was my number?
- 7.I thought of a number, multiplied it by 4 and added 1. I got 13. What was my number?
- 8.Magic trick! Think of 19. Double it, add 12, halve it, then take away 19. What number do you get?
- 9.I thought of a number, added 1 and then doubled it. I got 38. What was my number?
- 10.Magic trick! Think of 5. Double it, add 10, halve it, then take away 5. What number do you get?
- 11.Magic trick! Think of 14. Double it, add 16, halve it, then take away 14. What number do you get?
- 12.Think of 10. Multiply it by 3, then add 1. What number do you end with?
- 13.Think of 8. Multiply it by 3, then add 5. What number do you end with?
- 14.I thought of a number, added 1 and then doubled it. I got 14. What was my number?
- 15.Think of 15. Multiply it by 3, then add 9. What number do you end with?
- 16.I thought of a number, added 8 and then doubled it. I got 40. What was my number?
- 17.Magic trick! Think of 15. Double it, add 10, halve it, then take away 15. What number do you get?
- 18.Think of 10. Multiply it by 5, then add 2. What number do you end with?
- 19.Think of 11. Multiply it by 2, then add 4. What number do you end with?
- 20.I thought of a number, added 7 and then doubled it. I got 28. What was my number?
- 21.Magic trick! Think of 6. Double it, add 12, halve it, then take away 6. What number do you get?
- 22.I thought of a number, added 3 and then doubled it. I got 18. What was my number?
- 23.I thought of a number, multiplied it by 3 and added 5. I got 23. What was my number?
- 24.Think of 10. Multiply it by 5, then add 8. What number do you end with?
- 25.Think of 9. Multiply it by 5, then add 7. What number do you end with?
- 26.Think of 14. Multiply it by 2, then add 1. What number do you end with?
- 27.I thought of a number, multiplied it by 4 and added 5. I got 17. What was my number?
- 28.Think of 15. Multiply it by 3, then add 2. What number do you end with?
- 29.Think of 12. Multiply it by 3, then add 4. What number do you end with?
- 30.Magic trick! Think of 3. Double it, add 18, halve it, then take away 3. What number do you get?
- 31.Think of 12. Multiply it by 4, then add 8. What number do you end with?
- 32.Magic trick! Think of 11. Double it, add 4, halve it, then take away 11. What number do you get?
- 33.Magic trick! Think of 15. Double it, add 12, halve it, then take away 15. What number do you get?
- 34.I thought of a number, added 2 and then doubled it. I got 28. What was my number?
- 35.Think of 13. Multiply it by 2, then add 3. What number do you end with?
- 36.Magic trick! Think of 16. Double it, add 18, halve it, then take away 16. What number do you get?
- 37.I thought of a number, multiplied it by 3 and added 1. I got 43. What was my number?
- 38.Think of 8. Multiply it by 4, then add 7. What number do you end with?
- 39.I thought of a number, multiplied it by 2 and added 8. I got 38. What was my number?
- 40.I thought of a number, multiplied it by 3 and added 5. I got 38. What was my number?
Answer key
- 20
- 28
- 9
- 7
- 5
- 15
- 3
- 6
- 18
- 5
- 8
- 31
- 29
- 6
- 54
- 12
- 5
- 52
- 26
- 7
- 6
- 6
- 6
- 58
- 52
- 29
- 3
- 47
- 40
- 9
- 56
- 2
- 6
- 12
- 29
- 9
- 14
- 39
- 15
- 11
Free maths tricks lessons, practice and worksheets at talentjr.in/maths-tricks