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, multiplied it by 2 and added 8. I got 36. What was my number?
- 2.Magic trick! Think of 15. Double it, add 4, halve it, then take away 15. What number do you get?
- 3.Magic trick! Think of 14. Double it, add 4, halve it, then take away 14. What number do you get?
- 4.Magic trick! Think of 18. Double it, add 6, halve it, then take away 18. What number do you get?
- 5.I thought of a number, multiplied it by 4 and added 5. I got 29. What was my number?
- 6.Think of 13. Multiply it by 4, then add 7. What number do you end with?
- 7.I thought of a number, added 6 and then doubled it. I got 38. What was my number?
- 8.I thought of a number, added 5 and then doubled it. I got 34. What was my number?
- 9.Think of 12. Multiply it by 5, then add 3. What number do you end with?
- 10.Magic trick! Think of 17. Double it, add 10, halve it, then take away 17. What number do you get?
- 11.I thought of a number, multiplied it by 5 and added 1. I got 16. What was my number?
- 12.Magic trick! Think of 10. Double it, add 4, halve it, then take away 10. What number do you get?
- 13.Think of 4. Multiply it by 4, then add 8. What number do you end with?
- 14.Magic trick! Think of 2. Double it, add 8, halve it, then take away 2. What number do you get?
- 15.Think of 3. Multiply it by 3, then add 3. What number do you end with?
- 16.Think of 4. Multiply it by 4, then add 1. What number do you end with?
- 17.I thought of a number, multiplied it by 4 and added 3. I got 23. What was my number?
- 18.Think of 4. Multiply it by 3, then add 5. What number do you end with?
- 19.I thought of a number, multiplied it by 5 and added 9. I got 69. What was my number?
- 20.Magic trick! Think of 13. Double it, add 14, halve it, then take away 13. What number do you get?
- 21.I thought of a number, added 5 and then doubled it. I got 30. What was my number?
- 22.I thought of a number, multiplied it by 5 and added 8. I got 58. What was my number?
- 23.I thought of a number, multiplied it by 2 and added 1. I got 11. What was my number?
- 24.I thought of a number, multiplied it by 4 and added 2. I got 58. What was my number?
- 25.I thought of a number, multiplied it by 2 and added 6. I got 22. What was my number?
- 26.I thought of a number, multiplied it by 3 and added 8. I got 41. What was my number?
- 27.Think of 13. Multiply it by 4, then add 5. What number do you end with?
- 28.Think of 12. Multiply it by 3, then add 6. What number do you end with?
- 29.Magic trick! Think of 9. Double it, add 18, halve it, then take away 9. What number do you get?
- 30.I thought of a number, multiplied it by 5 and added 7. I got 82. What was my number?
- 31.I thought of a number, added 5 and then doubled it. I got 26. What was my number?
- 32.Think of 4. Multiply it by 5, then add 8. What number do you end with?
- 33.Think of 10. Multiply it by 2, then add 9. What number do you end with?
- 34.Magic trick! Think of 20. Double it, add 14, halve it, then take away 20. What number do you get?
- 35.Think of 5. Multiply it by 3, then add 5. What number do you end with?
- 36.Magic trick! Think of 16. Double it, add 14, halve it, then take away 16. What number do you get?
- 37.I thought of a number, added 5 and then doubled it. I got 24. What was my number?
- 38.Magic trick! Think of 18. Double it, add 14, halve it, then take away 18. What number do you get?
- 39.I thought of a number, multiplied it by 2 and added 1. I got 17. What was my number?
- 40.I thought of a number, added 6 and then doubled it. I got 50. What was my number?
Answer key
- 14
- 2
- 2
- 3
- 6
- 59
- 13
- 12
- 63
- 5
- 3
- 2
- 24
- 4
- 12
- 17
- 5
- 17
- 12
- 7
- 10
- 10
- 5
- 14
- 8
- 11
- 57
- 42
- 9
- 15
- 8
- 28
- 29
- 7
- 20
- 7
- 7
- 7
- 8
- 19
Free maths tricks lessons, practice and worksheets at talentjr.in/maths-tricks