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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 634 · 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 37 and take away the sum of its digits. What do you get?
  2. 2.425? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.3?32 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.24? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 13 and take away the sum of its digits. What do you get?
  6. 6.?813 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 36 and take away the sum of its digits. What do you get?
  8. 8.?748 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 62 and take away the sum of its digits. What do you get?
  10. 10.?899 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.397? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.660? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.4?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 77 and take away the sum of its digits. What do you get?
  15. 15.7?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 98 and take away the sum of its digits. What do you get?
  17. 17.?691 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 20 and take away the sum of its digits. What do you get?
  19. 19.718? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?015 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 48 and take away the sum of its digits. What do you get?
  22. 22.Take 56 and take away the sum of its digits. What do you get?
  23. 23.Take 81 and take away the sum of its digits. What do you get?
  24. 24.Take 95 and take away the sum of its digits. What do you get?
  25. 25.67?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.290? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 25 and take away the sum of its digits. What do you get?
  28. 28.?601 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?67 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.45?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?060 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.20?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.4?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.59? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?991 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.118? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.1?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.633? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 11 and take away the sum of its digits. What do you get?
  40. 40.3?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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