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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 857 · 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 73 and take away the sum of its digits. What do you get?
  2. 2.?19 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?73 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 19 and take away the sum of its digits. What do you get?
  5. 5.Take 70 and take away the sum of its digits. What do you get?
  6. 6.Take 45 and take away the sum of its digits. What do you get?
  7. 7.?020 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.4?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?763 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.4?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 99 and take away the sum of its digits. What do you get?
  12. 12.Take 83 and take away the sum of its digits. What do you get?
  13. 13.?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?349 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.73?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 67 and take away the sum of its digits. What do you get?
  17. 17.89?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?332 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 93 and take away the sum of its digits. What do you get?
  20. 20.Take 77 and take away the sum of its digits. What do you get?
  21. 21.311? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.284? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?101 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 82 and take away the sum of its digits. What do you get?
  25. 25.78?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 42 and take away the sum of its digits. What do you get?
  27. 27.?317 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.22?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.2?77 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 47 and take away the sum of its digits. What do you get?
  31. 31.61?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 39 and take away the sum of its digits. What do you get?
  33. 33.2?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.8?77 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.6?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.1?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 15 and take away the sum of its digits. What do you get?
  38. 38.?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?584 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?555 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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