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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 6 · 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 44 and take away the sum of its digits. What do you get?
  2. 2.Take 71 and take away the sum of its digits. What do you get?
  3. 3.530? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 31 and take away the sum of its digits. What do you get?
  5. 5.108? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?870 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.7?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 42 and take away the sum of its digits. What do you get?
  10. 10.Take 76 and take away the sum of its digits. What do you get?
  11. 11.64?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 51 and take away the sum of its digits. What do you get?
  13. 13.?06 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 15 and take away the sum of its digits. What do you get?
  15. 15.269? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 86 and take away the sum of its digits. What do you get?
  17. 17.Take 77 and take away the sum of its digits. What do you get?
  18. 18.Take 49 and take away the sum of its digits. What do you get?
  19. 19.Take 46 and take away the sum of its digits. What do you get?
  20. 20.Take 39 and take away the sum of its digits. What do you get?
  21. 21.19?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.827? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.579? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.5?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.611? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?788 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?679 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.6?38 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.6?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?92 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 85 and take away the sum of its digits. What do you get?
  32. 32.?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 24 and take away the sum of its digits. What do you get?
  34. 34.7?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.604? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.4?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.630? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.5?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 94 and take away the sum of its digits. What do you get?
  40. 40.5?87 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 36
  2. 63
  3. 1
  4. 27
  5. 9
  6. 3
  7. 8
  8. 3
  9. 36
  10. 63
  11. 6
  12. 45
  13. 3
  14. 9
  15. 1
  16. 72
  17. 63
  18. 36
  19. 36
  20. 27
  21. 1
  22. 1
  23. 6
  24. 2
  25. 1
  26. 4
  27. 5
  28. 1
  29. 3
  30. 7
  31. 72
  32. 1
  33. 18
  34. 1
  35. 8
  36. 4
  37. 9
  38. 1
  39. 81
  40. 7

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