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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 199 · 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 34 and take away the sum of its digits. What do you get?
  2. 2.Take 85 and take away the sum of its digits. What do you get?
  3. 3.48?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.71?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?008 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 40 and take away the sum of its digits. What do you get?
  7. 7.Take 62 and take away the sum of its digits. What do you get?
  8. 8.Take 36 and take away the sum of its digits. What do you get?
  9. 9.?995 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.56?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 51 and take away the sum of its digits. What do you get?
  12. 12.Take 74 and take away the sum of its digits. What do you get?
  13. 13.?025 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.5?41 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.48?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.73?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.8?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.426? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 69 and take away the sum of its digits. What do you get?
  20. 20.Take 29 and take away the sum of its digits. What do you get?
  21. 21.Take 31 and take away the sum of its digits. What do you get?
  22. 22.Take 82 and take away the sum of its digits. What do you get?
  23. 23.?194 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.3?89 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.366? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.71? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.7?55 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?25 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.9?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 96 and take away the sum of its digits. What do you get?
  31. 31.64?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?552 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 60 and take away the sum of its digits. What do you get?
  34. 34.?987 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.31?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.82?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.3?74 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 63 and take away the sum of its digits. What do you get?
  39. 39.1?38 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 24 and take away the sum of its digits. What do you get?

Answer key

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

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