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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 626 · 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.?830 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?274 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.19?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.83?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 74 and take away the sum of its digits. What do you get?
  6. 6.3?94 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.115? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.50?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 16 and take away the sum of its digits. What do you get?
  10. 10.?83 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?745 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 40 and take away the sum of its digits. What do you get?
  13. 13.Take 26 and take away the sum of its digits. What do you get?
  14. 14.?507 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.58?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.30?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.727? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.98? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.655? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.249? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.5?25 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.4?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.24?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?790 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 86 and take away the sum of its digits. What do you get?
  26. 26.?668 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.191? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.11? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.48?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.50?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.4?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 87 and take away the sum of its digits. What do you get?
  33. 33.4?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 75 and take away the sum of its digits. What do you get?
  35. 35.Take 37 and take away the sum of its digits. What do you get?
  36. 36.?852 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 93 and take away the sum of its digits. What do you get?
  38. 38.300? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.2?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.5?9 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. 5
  3. 9
  4. 7
  5. 63
  6. 2
  7. 2
  8. 1
  9. 9
  10. 7
  11. 2
  12. 36
  13. 18
  14. 6
  15. 6
  16. 2
  17. 2
  18. 1
  19. 2
  20. 3
  21. 6
  22. 4
  23. 4
  24. 2
  25. 72
  26. 7
  27. 7
  28. 7
  29. 2
  30. 4
  31. 6
  32. 72
  33. 9
  34. 63
  35. 27
  36. 3
  37. 81
  38. 6
  39. 4
  40. 4

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