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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 283 · 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.?97 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.270? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?006 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.489? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?674 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 28 and take away the sum of its digits. What do you get?
  7. 7.7?81 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.26?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 24 and take away the sum of its digits. What do you get?
  10. 10.?919 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 29 and take away the sum of its digits. What do you get?
  12. 12.?394 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 97 and take away the sum of its digits. What do you get?
  14. 14.7?98 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 73 and take away the sum of its digits. What do you get?
  16. 16.130? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 13 and take away the sum of its digits. What do you get?
  18. 18.1?39 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 15 and take away the sum of its digits. What do you get?
  20. 20.Take 36 and take away the sum of its digits. What do you get?
  21. 21.94? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.668? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.58?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.80?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.2?41 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 70 and take away the sum of its digits. What do you get?
  27. 27.?147 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.471? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.749? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.24?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 68 and take away the sum of its digits. What do you get?
  32. 32.Take 74 and take away the sum of its digits. What do you get?
  33. 33.?850 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.11?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 44 and take away the sum of its digits. What do you get?
  36. 36.Take 88 and take away the sum of its digits. What do you get?
  37. 37.4?11 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.143? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?102 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.10? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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