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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 337 · 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.?388 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.2?91 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.19?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 66 and take away the sum of its digits. What do you get?
  5. 5.?447 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 12 and take away the sum of its digits. What do you get?
  7. 7.Take 72 and take away the sum of its digits. What do you get?
  8. 8.Take 36 and take away the sum of its digits. What do you get?
  9. 9.7?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 24 and take away the sum of its digits. What do you get?
  11. 11.Take 97 and take away the sum of its digits. What do you get?
  12. 12.6?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.607? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.50?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.687? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?668 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 80 and take away the sum of its digits. What do you get?
  18. 18.82? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.460? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 88 and take away the sum of its digits. What do you get?
  21. 21.?899 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.569? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 47 and take away the sum of its digits. What do you get?
  24. 24.?393 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?254 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.98? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?296 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.278? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 33 and take away the sum of its digits. What do you get?
  30. 30.578? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.392? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.678? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.2?06 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.361? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?99 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.67? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.17? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.70?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?204 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.3?26 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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