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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 698 · 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 31 and take away the sum of its digits. What do you get?
  2. 2.54?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?640 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.700? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.12?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.8?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.204? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?046 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 95 and take away the sum of its digits. What do you get?
  10. 10.Take 92 and take away the sum of its digits. What do you get?
  11. 11.?093 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.7?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 11 and take away the sum of its digits. What do you get?
  14. 14.?94 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?734 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.87?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.484? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 34 and take away the sum of its digits. What do you get?
  19. 19.1?73 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.1?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.3?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.86?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?602 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.79?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 89 and take away the sum of its digits. What do you get?
  26. 26.84?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.90? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?107 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 54 and take away the sum of its digits. What do you get?
  30. 30.57?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.705? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.1?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.2?98 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 88 and take away the sum of its digits. What do you get?
  35. 35.Take 33 and take away the sum of its digits. What do you get?
  36. 36.?488 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.59?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.668? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 12 and take away the sum of its digits. What do you get?
  40. 40.4?67 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. 8
  3. 8
  4. 2
  5. 5
  6. 8
  7. 3
  8. 8
  9. 81
  10. 81
  11. 6
  12. 2
  13. 9
  14. 5
  15. 4
  16. 4
  17. 2
  18. 27
  19. 7
  20. 7
  21. 2
  22. 7
  23. 1
  24. 2
  25. 72
  26. 5
  27. 9
  28. 1
  29. 45
  30. 8
  31. 6
  32. 1
  33. 8
  34. 72
  35. 27
  36. 7
  37. 8
  38. 7
  39. 9
  40. 1

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