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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 985 · 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.?06 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 99 and take away the sum of its digits. What do you get?
  3. 3.Take 44 and take away the sum of its digits. What do you get?
  4. 4.Take 47 and take away the sum of its digits. What do you get?
  5. 5.Take 33 and take away the sum of its digits. What do you get?
  6. 6.Take 89 and take away the sum of its digits. What do you get?
  7. 7.Take 27 and take away the sum of its digits. What do you get?
  8. 8.477? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.118? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 67 and take away the sum of its digits. What do you get?
  11. 11.6?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 65 and take away the sum of its digits. What do you get?
  13. 13.79?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 40 and take away the sum of its digits. What do you get?
  15. 15.Take 81 and take away the sum of its digits. What do you get?
  16. 16.18?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.9?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 82 and take away the sum of its digits. What do you get?
  19. 19.?910 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.1?56 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.338? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.220? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.86?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.8?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.327? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?593 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 21 and take away the sum of its digits. What do you get?
  28. 28.?134 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.887? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.389? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.54?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 26 and take away the sum of its digits. What do you get?
  33. 33.Take 63 and take away the sum of its digits. What do you get?
  34. 34.?160 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.74?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 39 and take away the sum of its digits. What do you get?
  37. 37.Take 61 and take away the sum of its digits. What do you get?
  38. 38.?079 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?101 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 42 and take away the sum of its digits. What do you get?

Answer key

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

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