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 28. What was my number?
- 2.Magic trick! Think of 4. Double it, add 16, halve it, then take away 4. What number do you get?
- 3.Magic trick! Think of 2. Double it, add 14, halve it, then take away 2. What number do you get?
- 4.Think of 12. Multiply it by 3, then add 7. What number do you end with?
- 5.Magic trick! Think of 8. Double it, add 12, halve it, then take away 8. What number do you get?
- 6.Magic trick! Think of 7. Double it, add 8, halve it, then take away 7. What number do you get?
- 7.Think of 12. Multiply it by 2, then add 1. What number do you end with?
- 8.I thought of a number, multiplied it by 2 and added 8. I got 26. What was my number?
- 9.I thought of a number, multiplied it by 2 and added 3. I got 13. What was my number?
- 10.I thought of a number, added 7 and then doubled it. I got 20. What was my number?
- 11.I thought of a number, added 9 and then doubled it. I got 50. What was my number?
- 12.I thought of a number, added 7 and then doubled it. I got 48. What was my number?
- 13.Think of 13. Multiply it by 2, then add 5. What number do you end with?
- 14.I thought of a number, added 7 and then doubled it. I got 24. What was my number?
- 15.Think of 2. Multiply it by 5, then add 3. What number do you end with?
- 16.I thought of a number, added 4 and then doubled it. I got 30. What was my number?
- 17.I thought of a number, multiplied it by 3 and added 8. I got 26. What was my number?
- 18.I thought of a number, added 2 and then doubled it. I got 34. What was my number?
- 19.I thought of a number, multiplied it by 2 and added 4. I got 14. What was my number?
- 20.I thought of a number, added 2 and then doubled it. I got 40. What was my number?
- 21.I thought of a number, added 4 and then doubled it. I got 46. What was my number?
- 22.I thought of a number, multiplied it by 2 and added 4. I got 10. What was my number?
- 23.Magic trick! Think of 4. Double it, add 14, halve it, then take away 4. What number do you get?
- 24.Magic trick! Think of 3. Double it, add 18, halve it, then take away 3. What number do you get?
- 25.Magic trick! Think of 14. Double it, add 6, halve it, then take away 14. What number do you get?
- 26.Magic trick! Think of 8. Double it, add 16, halve it, then take away 8. What number do you get?
- 27.I thought of a number, multiplied it by 5 and added 1. I got 11. What was my number?
- 28.Think of 13. Multiply it by 3, then add 3. What number do you end with?
- 29.Think of 2. Multiply it by 3, then add 3. What number do you end with?
- 30.Think of 5. Multiply it by 2, then add 5. What number do you end with?
- 31.I thought of a number, added 6 and then doubled it. I got 22. What was my number?
- 32.Magic trick! Think of 6. Double it, add 18, halve it, then take away 6. What number do you get?
- 33.I thought of a number, added 8 and then doubled it. I got 52. What was my number?
- 34.Magic trick! Think of 17. Double it, add 6, halve it, then take away 17. What number do you get?
- 35.I thought of a number, added 1 and then doubled it. I got 24. What was my number?
- 36.I thought of a number, added 6 and then doubled it. I got 52. What was my number?
- 37.I thought of a number, multiplied it by 3 and added 9. I got 51. What was my number?
- 38.Think of 15. Multiply it by 3, then add 7. What number do you end with?
- 39.I thought of a number, added 1 and then doubled it. I got 40. What was my number?
- 40.I thought of a number, multiplied it by 5 and added 5. I got 75. What was my number?
Answer key
- 9
- 8
- 7
- 43
- 6
- 4
- 25
- 9
- 5
- 3
- 16
- 17
- 31
- 5
- 13
- 11
- 6
- 15
- 5
- 18
- 19
- 3
- 7
- 9
- 3
- 8
- 2
- 42
- 9
- 15
- 5
- 9
- 18
- 3
- 11
- 20
- 14
- 52
- 19
- 14
Free maths tricks lessons, practice and worksheets at talentjr.in/maths-tricks