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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 292 · 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. 1.828? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?250 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?334 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?122 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.50?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.3?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 30 and take away the sum of its digits. What do you get?
  9. 9.7?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.5?58 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.2?56 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.762? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?480 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 79 and take away the sum of its digits. What do you get?
  15. 15.Take 97 and take away the sum of its digits. What do you get?
  16. 16.Take 98 and take away the sum of its digits. What do you get?
  17. 17.Take 44 and take away the sum of its digits. What do you get?
  18. 18.66? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.393? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.24?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.28?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 60 and take away the sum of its digits. What do you get?
  23. 23.877? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 39 and take away the sum of its digits. What do you get?
  25. 25.1?36 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.3?13 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 93 and take away the sum of its digits. What do you get?
  28. 28.Take 27 and take away the sum of its digits. What do you get?
  29. 29.Take 80 and take away the sum of its digits. What do you get?
  30. 30.5?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.139? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.14? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 62 and take away the sum of its digits. What do you get?
  34. 34.36?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?165 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?012 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.166? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.4?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.18?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.63?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. 2
  3. 8
  4. 1
  5. 4
  6. 9
  7. 7
  8. 27
  9. 7
  10. 9
  11. 5
  12. 3
  13. 6
  14. 63
  15. 81
  16. 81
  17. 36
  18. 6
  19. 3
  20. 8
  21. 1
  22. 54
  23. 5
  24. 27
  25. 8
  26. 2
  27. 81
  28. 18
  29. 72
  30. 9
  31. 5
  32. 4
  33. 54
  34. 9
  35. 6
  36. 6
  37. 5
  38. 9
  39. 8
  40. 9

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