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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 866 · 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. 1.855? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.7?69 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.196? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 51 and take away the sum of its digits. What do you get?
  5. 5.?536 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.69?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 47 and take away the sum of its digits. What do you get?
  8. 8.28? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?006 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 54 and take away the sum of its digits. What do you get?
  11. 11.Take 69 and take away the sum of its digits. What do you get?
  12. 12.90? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 28 and take away the sum of its digits. What do you get?
  14. 14.18?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 30 and take away the sum of its digits. What do you get?
  16. 16.123? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 82 and take away the sum of its digits. What do you get?
  18. 18.5?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.2?73 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 93 and take away the sum of its digits. What do you get?
  21. 21.155? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.402? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.608? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.68?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.336? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.7?88 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.12?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?535 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?982 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.80?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.601? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?56 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.754? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 37 and take away the sum of its digits. What do you get?
  35. 35.541? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 87 and take away the sum of its digits. What do you get?
  37. 37.Take 32 and take away the sum of its digits. What do you get?
  38. 38.41?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?401 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.5?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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