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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 867 · 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. 1.123? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?640 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?708 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 31 and take away the sum of its digits. What do you get?
  5. 5.46? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 72 and take away the sum of its digits. What do you get?
  7. 7.293? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?146 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.3?95 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.47?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.71?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 51 and take away the sum of its digits. What do you get?
  13. 13.109? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?14 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?294 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?235 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.35? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?872 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.720? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.6?25 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?83 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.19?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.31?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.40? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?76 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.Take 37 and take away the sum of its digits. What do you get?
  28. 28.16?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.1?11 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 88 and take away the sum of its digits. What do you get?
  31. 31.8?11 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 57 and take away the sum of its digits. What do you get?
  33. 33.175? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?91 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 44 and take away the sum of its digits. What do you get?
  36. 36.8?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.299? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?208 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.8?72 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.1?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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