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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 497 · 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. 1.740? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?313 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 63 and take away the sum of its digits. What do you get?
  4. 4.?750 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.405? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.54?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?975 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 85 and take away the sum of its digits. What do you get?
  9. 9.?81 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 16 and take away the sum of its digits. What do you get?
  11. 11.Take 20 and take away the sum of its digits. What do you get?
  12. 12.8?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.26?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.8?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?686 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 79 and take away the sum of its digits. What do you get?
  17. 17.Take 17 and take away the sum of its digits. What do you get?
  18. 18.13?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?134 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 42 and take away the sum of its digits. What do you get?
  21. 21.379? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 87 and take away the sum of its digits. What do you get?
  23. 23.Take 50 and take away the sum of its digits. What do you get?
  24. 24.?278 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.16?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 48 and take away the sum of its digits. What do you get?
  27. 27.58?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.68? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.104? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 94 and take away the sum of its digits. What do you get?
  31. 31.Take 11 and take away the sum of its digits. What do you get?
  32. 32.1?67 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?787 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 68 and take away the sum of its digits. What do you get?
  35. 35.3?67 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.7?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 22 and take away the sum of its digits. What do you get?
  38. 38.5?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.4?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.13?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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