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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 119 · 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.?403 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 71 and take away the sum of its digits. What do you get?
  3. 3.Take 33 and take away the sum of its digits. What do you get?
  4. 4.Take 77 and take away the sum of its digits. What do you get?
  5. 5.59?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 96 and take away the sum of its digits. What do you get?
  7. 7.31?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.35?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 41 and take away the sum of its digits. What do you get?
  10. 10.Take 60 and take away the sum of its digits. What do you get?
  11. 11.Take 81 and take away the sum of its digits. What do you get?
  12. 12.?255 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.58?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.8?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?022 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 35 and take away the sum of its digits. What do you get?
  17. 17.71?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.2?56 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.798? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.44?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 31 and take away the sum of its digits. What do you get?
  22. 22.2?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.8?54 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?240 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.405? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.591? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.8?56 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.26?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.531? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 74 and take away the sum of its digits. What do you get?
  31. 31.?12 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.57? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 56 and take away the sum of its digits. What do you get?
  34. 34.Take 32 and take away the sum of its digits. What do you get?
  35. 35.40?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.1?54 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.18?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.1?14 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.75?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 78 and take away the sum of its digits. What do you get?

Answer key

  1. 2
  2. 63
  3. 27
  4. 63
  5. 4
  6. 81
  7. 3
  8. 6
  9. 36
  10. 54
  11. 72
  12. 6
  13. 7
  14. 4
  15. 5
  16. 27
  17. 7
  18. 5
  19. 3
  20. 6
  21. 27
  22. 6
  23. 1
  24. 3
  25. 9
  26. 3
  27. 8
  28. 1
  29. 9
  30. 63
  31. 6
  32. 6
  33. 45
  34. 27
  35. 1
  36. 8
  37. 6
  38. 3
  39. 5
  40. 63

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