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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 498 · 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. 1.9?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 63 and take away the sum of its digits. What do you get?
  3. 3.210? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 80 and take away the sum of its digits. What do you get?
  5. 5.?752 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?139 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.36?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.26?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 17 and take away the sum of its digits. What do you get?
  10. 10.Take 66 and take away the sum of its digits. What do you get?
  11. 11.880? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.18? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 93 and take away the sum of its digits. What do you get?
  14. 14.674? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.7?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.6?49 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.507? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?115 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?31 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.4?80 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 24 and take away the sum of its digits. What do you get?
  22. 22.Take 28 and take away the sum of its digits. What do you get?
  23. 23.604? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 48 and take away the sum of its digits. What do you get?
  25. 25.329? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.5?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 35 and take away the sum of its digits. What do you get?
  28. 28.?57 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 56 and take away the sum of its digits. What do you get?
  30. 30.829? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 23 and take away the sum of its digits. What do you get?
  32. 32.?71 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.27?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?028 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.775? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.8?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 58 and take away the sum of its digits. What do you get?
  38. 38.Take 68 and take away the sum of its digits. What do you get?
  39. 39.Take 76 and take away the sum of its digits. What do you get?
  40. 40.?183 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 7
  2. 54
  3. 6
  4. 72
  5. 4
  6. 5
  7. 7
  8. 4
  9. 9
  10. 54
  11. 2
  12. 9
  13. 81
  14. 1
  15. 8
  16. 8
  17. 6
  18. 2
  19. 5
  20. 6
  21. 18
  22. 18
  23. 8
  24. 36
  25. 4
  26. 9
  27. 27
  28. 6
  29. 45
  30. 8
  31. 18
  32. 1
  33. 7
  34. 8
  35. 8
  36. 9
  37. 45
  38. 54
  39. 63
  40. 6

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