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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 989 · 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.?94 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 97 and take away the sum of its digits. What do you get?
  3. 3.60?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.606? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.6?48 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?494 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.22?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 52 and take away the sum of its digits. What do you get?
  9. 9.Take 17 and take away the sum of its digits. What do you get?
  10. 10.?478 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 21 and take away the sum of its digits. What do you get?
  12. 12.8?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.6?56 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.1?18 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 23 and take away the sum of its digits. What do you get?
  16. 16.?732 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?308 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 59 and take away the sum of its digits. What do you get?
  19. 19.Take 79 and take away the sum of its digits. What do you get?
  20. 20.?73 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?170 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?168 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?926 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?103 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.733? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 63 and take away the sum of its digits. What do you get?
  27. 27.?361 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.7?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.1?83 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.56?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?025 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?870 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 83 and take away the sum of its digits. What do you get?
  34. 34.Take 24 and take away the sum of its digits. What do you get?
  35. 35.11?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 71 and take away the sum of its digits. What do you get?
  37. 37.197? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 78 and take away the sum of its digits. What do you get?
  39. 39.688? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 42 and take away the sum of its digits. What do you get?

Answer key

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

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