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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 597 · 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. 1.740? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 32 and take away the sum of its digits. What do you get?
  3. 3.709? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.6?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 46 and take away the sum of its digits. What do you get?
  6. 6.2?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.871? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?340 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 12 and take away the sum of its digits. What do you get?
  10. 10.?194 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.7?24 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.71?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.70?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?079 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?753 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.49?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 86 and take away the sum of its digits. What do you get?
  19. 19.521? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 88 and take away the sum of its digits. What do you get?
  21. 21.?586 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 24 and take away the sum of its digits. What do you get?
  23. 23.22?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 91 and take away the sum of its digits. What do you get?
  25. 25.24?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.41?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.62?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?920 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 68 and take away the sum of its digits. What do you get?
  30. 30.?101 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.2?96 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?521 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 71 and take away the sum of its digits. What do you get?
  34. 34.?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?910 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.5?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 25 and take away the sum of its digits. What do you get?
  38. 38.Take 26 and take away the sum of its digits. What do you get?
  39. 39.389? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.727? 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. 27
  3. 2
  4. 2
  5. 36
  6. 1
  7. 2
  8. 2
  9. 9
  10. 4
  11. 5
  12. 1
  13. 3
  14. 9
  15. 2
  16. 3
  17. 5
  18. 72
  19. 1
  20. 72
  21. 8
  22. 18
  23. 3
  24. 81
  25. 9
  26. 2
  27. 2
  28. 7
  29. 54
  30. 7
  31. 1
  32. 1
  33. 63
  34. 6
  35. 8
  36. 8
  37. 18
  38. 18
  39. 7
  40. 2

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