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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 943 · 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.?406 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.101? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 58 and take away the sum of its digits. What do you get?
  4. 4.2?61 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 80 and take away the sum of its digits. What do you get?
  6. 6.Take 88 and take away the sum of its digits. What do you get?
  7. 7.Take 71 and take away the sum of its digits. What do you get?
  8. 8.Take 61 and take away the sum of its digits. What do you get?
  9. 9.8?23 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 26 and take away the sum of its digits. What do you get?
  11. 11.767? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 17 and take away the sum of its digits. What do you get?
  13. 13.?919 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 49 and take away the sum of its digits. What do you get?
  15. 15.80? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 27 and take away the sum of its digits. What do you get?
  17. 17.Take 15 and take away the sum of its digits. What do you get?
  18. 18.861? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.540? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 96 and take away the sum of its digits. What do you get?
  21. 21.?635 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 13 and take away the sum of its digits. What do you get?
  24. 24.1?36 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?430 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 43 and take away the sum of its digits. What do you get?
  27. 27.552? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.3?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?058 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 84 and take away the sum of its digits. What do you get?
  31. 31.2?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.12?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 28 and take away the sum of its digits. What do you get?
  34. 34.Take 22 and take away the sum of its digits. What do you get?
  35. 35.?220 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?81 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 74 and take away the sum of its digits. What do you get?
  38. 38.188? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.3?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 94 and take away the sum of its digits. What do you get?

Answer key

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

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