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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 466 · 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. 1.52?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.19?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?365 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 79 and take away the sum of its digits. What do you get?
  5. 5.63?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 97 and take away the sum of its digits. What do you get?
  7. 7.Take 43 and take away the sum of its digits. What do you get?
  8. 8.Take 14 and take away the sum of its digits. What do you get?
  9. 9.Take 82 and take away the sum of its digits. What do you get?
  10. 10.64?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?105 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.3?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 94 and take away the sum of its digits. What do you get?
  14. 14.6?41 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.26?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?421 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.7?92 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 45 and take away the sum of its digits. What do you get?
  19. 19.?196 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.81?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.826? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 18 and take away the sum of its digits. What do you get?
  23. 23.Take 85 and take away the sum of its digits. What do you get?
  24. 24.9?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.313? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?925 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 13 and take away the sum of its digits. What do you get?
  28. 28.Take 25 and take away the sum of its digits. What do you get?
  29. 29.2?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.5?45 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.13?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.44?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 62 and take away the sum of its digits. What do you get?
  35. 35.14?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.8?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 95 and take away the sum of its digits. What do you get?
  38. 38.?644 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 56 and take away the sum of its digits. What do you get?
  40. 40.93? 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. 5
  3. 4
  4. 63
  5. 4
  6. 81
  7. 36
  8. 9
  9. 72
  10. 1
  11. 3
  12. 6
  13. 81
  14. 7
  15. 9
  16. 2
  17. 9
  18. 36
  19. 2
  20. 7
  21. 2
  22. 9
  23. 72
  24. 2
  25. 2
  26. 2
  27. 9
  28. 18
  29. 6
  30. 3
  31. 4
  32. 3
  33. 2
  34. 54
  35. 2
  36. 2
  37. 81
  38. 4
  39. 45
  40. 6

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