← Think of a number lesson New set →

Think of a Number Puzzles Worksheet

Maths tricks trick 6: Think of a number · Set 75 · 40 questions
TalentJR

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

Answer key

  1. 6
  2. 9
  3. 53
  4. 6
  5. 9
  6. 20
  7. 15
  8. 30
  9. 20
  10. 21
  11. 5
  12. 14
  13. 7
  14. 15
  15. 5
  16. 6
  17. 7
  18. 8
  19. 18
  20. 4
  21. 4
  22. 8
  23. 3
  24. 4
  25. 10
  26. 13
  27. 2
  28. 4
  29. 11
  30. 4
  31. 2
  32. 17
  33. 3
  34. 2
  35. 29
  36. 3
  37. 11
  38. 9
  39. 8
  40. 6

Free maths tricks lessons, practice and worksheets at talentjr.in/maths-tricks