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 3 and then doubled it. I got 34. What was my number?
- 2.Think of 9. Multiply it by 2, then add 3. What number do you end with?
- 3.I thought of a number, multiplied it by 3 and added 3. I got 21. What was my number?
- 4.I thought of a number, multiplied it by 3 and added 6. I got 42. What was my number?
- 5.Magic trick! Think of 18. Double it, add 14, halve it, then take away 18. What number do you get?
- 6.Magic trick! Think of 10. Double it, add 4, halve it, then take away 10. What number do you get?
- 7.I thought of a number, added 5 and then doubled it. I got 20. What was my number?
- 8.Magic trick! Think of 7. Double it, add 14, halve it, then take away 7. What number do you get?
- 9.Think of 12. Multiply it by 4, then add 5. What number do you end with?
- 10.I thought of a number, multiplied it by 5 and added 1. I got 16. What was my number?
- 11.I thought of a number, added 3 and then doubled it. I got 26. What was my number?
- 12.I thought of a number, added 9 and then doubled it. I got 58. What was my number?
- 13.I thought of a number, added 1 and then doubled it. I got 38. What was my number?
- 14.Magic trick! Think of 16. Double it, add 18, halve it, then take away 16. What number do you get?
- 15.I thought of a number, added 8 and then doubled it. I got 24. What was my number?
- 16.Magic trick! Think of 18. Double it, add 18, halve it, then take away 18. What number do you get?
- 17.Magic trick! Think of 12. Double it, add 6, halve it, then take away 12. What number do you get?
- 18.I thought of a number, added 3 and then doubled it. I got 42. What was my number?
- 19.Magic trick! Think of 8. Double it, add 8, halve it, then take away 8. What number do you get?
- 20.I thought of a number, added 4 and then doubled it. I got 44. What was my number?
- 21.I thought of a number, added 9 and then doubled it. I got 50. What was my number?
- 22.I thought of a number, multiplied it by 2 and added 7. I got 11. What was my number?
- 23.I thought of a number, added 1 and then doubled it. I got 32. What was my number?
- 24.Think of 3. Multiply it by 3, then add 7. What number do you end with?
- 25.I thought of a number, added 5 and then doubled it. I got 18. What was my number?
- 26.Magic trick! Think of 6. Double it, add 18, halve it, then take away 6. What number do you get?
- 27.I thought of a number, added 1 and then doubled it. I got 14. What was my number?
- 28.Think of 4. Multiply it by 5, then add 8. What number do you end with?
- 29.I thought of a number, added 5 and then doubled it. I got 44. What was my number?
- 30.I thought of a number, multiplied it by 2 and added 6. I got 24. What was my number?
- 31.Think of 14. Multiply it by 5, then add 8. What number do you end with?
- 32.I thought of a number, added 6 and then doubled it. I got 38. What was my number?
- 33.I thought of a number, added 5 and then doubled it. I got 40. What was my number?
- 34.I thought of a number, added 4 and then doubled it. I got 26. What was my number?
- 35.Think of 4. Multiply it by 5, then add 6. What number do you end with?
- 36.I thought of a number, added 7 and then doubled it. I got 20. What was my number?
- 37.Think of 7. Multiply it by 3, then add 6. What number do you end with?
- 38.I thought of a number, added 8 and then doubled it. I got 34. What was my number?
- 39.I thought of a number, multiplied it by 3 and added 5. I got 44. What was my number?
- 40.Think of 10. Multiply it by 3, then add 7. What number do you end with?
Answer key
- 14
- 21
- 6
- 12
- 7
- 2
- 5
- 7
- 53
- 3
- 10
- 20
- 18
- 9
- 4
- 9
- 3
- 18
- 4
- 18
- 16
- 2
- 15
- 16
- 4
- 9
- 6
- 28
- 17
- 9
- 78
- 13
- 15
- 9
- 26
- 3
- 27
- 9
- 13
- 37
Free maths tricks lessons, practice and worksheets at talentjr.in/maths-tricks