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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 863 · 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 82 and take away the sum of its digits. What do you get?
  2. 2.Take 92 and take away the sum of its digits. What do you get?
  3. 3.1?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.82?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 58 and take away the sum of its digits. What do you get?
  7. 7.33?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.2?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 32 and take away the sum of its digits. What do you get?
  10. 10.5?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?696 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.33?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.1?77 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 44 and take away the sum of its digits. What do you get?
  15. 15.4?48 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?416 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?47 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.840? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 60 and take away the sum of its digits. What do you get?
  20. 20.?843 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.454? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.3?72 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 93 and take away the sum of its digits. What do you get?
  24. 24.86?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?485 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?313 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.4?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.55?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.899? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 13 and take away the sum of its digits. What do you get?
  31. 31.76?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 34 and take away the sum of its digits. What do you get?
  33. 33.4?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 48 and take away the sum of its digits. What do you get?
  35. 35.805? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.8?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?308 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 71 and take away the sum of its digits. What do you get?
  39. 39.186? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.84?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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