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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 328 · 40 questions
TalentJR

The trick (Digits add to the 9 table): Add the digits you can see. Find the next number in the 9 table (9, 18, 27 …) above that total. The hidden digit is the difference. (Any number minus its digit sum is in the 9 table too.)

NameDateTime takenScore ___ / 40
  1. 1.Take 71 and take away the sum of its digits. What do you get?
  2. 2.Take 33 and take away the sum of its digits. What do you get?
  3. 3.69?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?115 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 73 and take away the sum of its digits. What do you get?
  6. 6.103? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 55 and take away the sum of its digits. What do you get?
  8. 8.60?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?584 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.7?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.5?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.6?92 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.852? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?145 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.12?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.7?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?942 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.8?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 62 and take away the sum of its digits. What do you get?
  20. 20.34?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 15 and take away the sum of its digits. What do you get?
  22. 22.8?56 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.2?06 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 46 and take away the sum of its digits. What do you get?
  25. 25.?676 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.66? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.5?72 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?714 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.869? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.9?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?447 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.883? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 53 and take away the sum of its digits. What do you get?
  34. 34.121? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.268? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.85?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 13 and take away the sum of its digits. What do you get?
  38. 38.Take 42 and take away the sum of its digits. What do you get?
  39. 39.3?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 24 and take away the sum of its digits. What do you get?

Answer key

  1. 63
  2. 27
  3. 9
  4. 2
  5. 63
  6. 5
  7. 45
  8. 4
  9. 1
  10. 6
  11. 1
  12. 1
  13. 3
  14. 8
  15. 6
  16. 2
  17. 3
  18. 1
  19. 54
  20. 4
  21. 9
  22. 8
  23. 1
  24. 36
  25. 8
  26. 6
  27. 4
  28. 6
  29. 4
  30. 7
  31. 3
  32. 8
  33. 45
  34. 5
  35. 2
  36. 4
  37. 9
  38. 36
  39. 5
  40. 18

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