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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 854 · 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.?937 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 85 and take away the sum of its digits. What do you get?
  3. 3.3?53 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 53 and take away the sum of its digits. What do you get?
  5. 5.89?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.28?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.17?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.162? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.5?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?778 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 88 and take away the sum of its digits. What do you get?
  12. 12.6?11 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.146? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 89 and take away the sum of its digits. What do you get?
  15. 15.Take 36 and take away the sum of its digits. What do you get?
  16. 16.Take 65 and take away the sum of its digits. What do you get?
  17. 17.628? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 39 and take away the sum of its digits. What do you get?
  19. 19.Take 31 and take away the sum of its digits. What do you get?
  20. 20.?58 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?050 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.69?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?875 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?14 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.3?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.777? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.4?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.81?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?025 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.50?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 40 and take away the sum of its digits. What do you get?
  32. 32.?001 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.67?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 55 and take away the sum of its digits. What do you get?
  35. 35.Take 45 and take away the sum of its digits. What do you get?
  36. 36.?676 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?730 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?465 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 26 and take away the sum of its digits. What do you get?
  40. 40.Take 32 and take away the sum of its digits. What do you get?

Answer key

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

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