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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 128 · 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.?357 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 55 and take away the sum of its digits. What do you get?
  3. 3.879? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.34? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?537 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.4?63 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 42 and take away the sum of its digits. What do you get?
  8. 8.Take 97 and take away the sum of its digits. What do you get?
  9. 9.Take 65 and take away the sum of its digits. What do you get?
  10. 10.5?31 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?095 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.8?56 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.354? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.683? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.196? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.812? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 53 and take away the sum of its digits. What do you get?
  18. 18.?350 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.5?65 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 72 and take away the sum of its digits. What do you get?
  21. 21.194? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.4?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.39?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.29?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.67?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?907 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?301 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.30?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.4?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.841? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?221 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?949 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.4?84 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 67 and take away the sum of its digits. What do you get?
  35. 35.?151 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 96 and take away the sum of its digits. What do you get?
  37. 37.556? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.19?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 27 and take away the sum of its digits. What do you get?
  40. 40.7?61 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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