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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 394 · 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. 1.73?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?817 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.46? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.33?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.3?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.2?61 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.1?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.109? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 96 and take away the sum of its digits. What do you get?
  10. 10.?577 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?974 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 60 and take away the sum of its digits. What do you get?
  13. 13.?753 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.426? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.5?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 91 and take away the sum of its digits. What do you get?
  17. 17.?339 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?597 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.196? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.343? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.700? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 29 and take away the sum of its digits. What do you get?
  23. 23.58?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.638? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 49 and take away the sum of its digits. What do you get?
  26. 26.8?67 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.79?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 73 and take away the sum of its digits. What do you get?
  29. 29.?154 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.35? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 39 and take away the sum of its digits. What do you get?
  32. 32.Take 89 and take away the sum of its digits. What do you get?
  33. 33.?931 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.27?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.61?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 98 and take away the sum of its digits. What do you get?
  37. 37.11? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?383 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.88?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?166 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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