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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 829 · 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 81 and take away the sum of its digits. What do you get?
  2. 2.Take 65 and take away the sum of its digits. What do you get?
  3. 3.Take 16 and take away the sum of its digits. What do you get?
  4. 4.?904 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.740? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.481? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.27?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 31 and take away the sum of its digits. What do you get?
  9. 9.6?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 41 and take away the sum of its digits. What do you get?
  11. 11.8?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?55 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 35 and take away the sum of its digits. What do you get?
  14. 14.2?77 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 47 and take away the sum of its digits. What do you get?
  16. 16.357? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.624? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.7?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 60 and take away the sum of its digits. What do you get?
  20. 20.6?96 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.71?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?74 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 86 and take away the sum of its digits. What do you get?
  24. 24.4?63 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?934 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 96 and take away the sum of its digits. What do you get?
  27. 27.48?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?43 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?710 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.36?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?951 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 22 and take away the sum of its digits. What do you get?
  33. 33.Take 45 and take away the sum of its digits. What do you get?
  34. 34.652? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?264 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.7?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.8?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 92 and take away the sum of its digits. What do you get?
  39. 39.86?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?383 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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