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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 781 · 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. 1.18?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.231? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?859 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 57 and take away the sum of its digits. What do you get?
  5. 5.Take 78 and take away the sum of its digits. What do you get?
  6. 6.Take 56 and take away the sum of its digits. What do you get?
  7. 7.Take 44 and take away the sum of its digits. What do you get?
  8. 8.Take 26 and take away the sum of its digits. What do you get?
  9. 9.283? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.485? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?559 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 68 and take away the sum of its digits. What do you get?
  13. 13.188? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.35?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?491 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 13 and take away the sum of its digits. What do you get?
  17. 17.61?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 18 and take away the sum of its digits. What do you get?
  19. 19.56?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?23 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?41 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.5?24 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.38?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 29 and take away the sum of its digits. What do you get?
  25. 25.Take 49 and take away the sum of its digits. What do you get?
  26. 26.?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 92 and take away the sum of its digits. What do you get?
  30. 30.5?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 22 and take away the sum of its digits. What do you get?
  32. 32.?042 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 40 and take away the sum of its digits. What do you get?
  34. 34.78?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 20 and take away the sum of its digits. What do you get?
  36. 36.70?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.775? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 12 and take away the sum of its digits. What do you get?
  39. 39.224? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.3?28 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 2
  2. 3
  3. 5
  4. 45
  5. 63
  6. 45
  7. 36
  8. 18
  9. 5
  10. 1
  11. 8
  12. 54
  13. 1
  14. 5
  15. 4
  16. 9
  17. 8
  18. 9
  19. 7
  20. 4
  21. 4
  22. 7
  23. 4
  24. 18
  25. 36
  26. 8
  27. 6
  28. 1
  29. 81
  30. 7
  31. 18
  32. 3
  33. 36
  34. 1
  35. 18
  36. 1
  37. 8
  38. 9
  39. 1
  40. 5

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