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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 890 · 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. 1.4?51 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.69?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?887 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.27?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.2?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 21 and take away the sum of its digits. What do you get?
  7. 7.Take 43 and take away the sum of its digits. What do you get?
  8. 8.?210 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?080 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.432? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 20 and take away the sum of its digits. What do you get?
  12. 12.1?97 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.57?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.765? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?568 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?85 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 56 and take away the sum of its digits. What do you get?
  18. 18.19? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?835 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?834 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?943 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.1?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?733 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.24?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?067 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.738? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?263 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.231? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?156 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.1?51 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.514? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.20?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 99 and take away the sum of its digits. What do you get?
  34. 34.24?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 97 and take away the sum of its digits. What do you get?
  36. 36.Take 54 and take away the sum of its digits. What do you get?
  37. 37.250? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.420? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.262? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 90 and take away the sum of its digits. What do you get?

Answer key

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

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