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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 262 · 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 30 and take away the sum of its digits. What do you get?
  2. 2.Take 25 and take away the sum of its digits. What do you get?
  3. 3.Take 40 and take away the sum of its digits. What do you get?
  4. 4.8?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 89 and take away the sum of its digits. What do you get?
  6. 6.?492 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.4?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?79 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.348? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 68 and take away the sum of its digits. What do you get?
  11. 11.4?13 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 81 and take away the sum of its digits. What do you get?
  13. 13.?021 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.224? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?114 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.209? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 91 and take away the sum of its digits. What do you get?
  18. 18.25?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.11?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 59 and take away the sum of its digits. What do you get?
  22. 22.572? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?583 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?636 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?958 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 19 and take away the sum of its digits. What do you get?
  27. 27.?249 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?899 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.4?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.8?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.740? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?73 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?517 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 70 and take away the sum of its digits. What do you get?
  35. 35.?620 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 27 and take away the sum of its digits. What do you get?
  37. 37.73?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 63 and take away the sum of its digits. What do you get?
  39. 39.?699 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?637 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 27
  2. 18
  3. 36
  4. 7
  5. 72
  6. 3
  7. 5
  8. 2
  9. 3
  10. 54
  11. 1
  12. 72
  13. 6
  14. 1
  15. 3
  16. 7
  17. 81
  18. 4
  19. 7
  20. 4
  21. 45
  22. 4
  23. 2
  24. 3
  25. 5
  26. 9
  27. 3
  28. 1
  29. 4
  30. 9
  31. 7
  32. 8
  33. 5
  34. 63
  35. 1
  36. 18
  37. 7
  38. 54
  39. 3
  40. 2

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