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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 608 · 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.?416 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?026 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 67 and take away the sum of its digits. What do you get?
  4. 4.1?21 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.383? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 19 and take away the sum of its digits. What do you get?
  7. 7.45?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?704 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?484 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 15 and take away the sum of its digits. What do you get?
  11. 11.Take 87 and take away the sum of its digits. What do you get?
  12. 12.?703 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.2?56 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 39 and take away the sum of its digits. What do you get?
  15. 15.Take 49 and take away the sum of its digits. What do you get?
  16. 16.357? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.2?28 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?101 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 14 and take away the sum of its digits. What do you get?
  20. 20.Take 53 and take away the sum of its digits. What do you get?
  21. 21.59?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?294 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 26 and take away the sum of its digits. What do you get?
  24. 24.741? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?305 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 31 and take away the sum of its digits. What do you get?
  27. 27.Take 66 and take away the sum of its digits. What do you get?
  28. 28.364? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 63 and take away the sum of its digits. What do you get?
  30. 30.?991 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?998 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 84 and take away the sum of its digits. What do you get?
  33. 33.?966 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 11 and take away the sum of its digits. What do you get?
  35. 35.?697 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.2?25 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?390 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.51?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.740? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.7?16 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. 1
  3. 54
  4. 5
  5. 4
  6. 9
  7. 8
  8. 7
  9. 2
  10. 9
  11. 72
  12. 8
  13. 5
  14. 27
  15. 36
  16. 3
  17. 6
  18. 7
  19. 9
  20. 45
  21. 2
  22. 3
  23. 18
  24. 6
  25. 1
  26. 27
  27. 54
  28. 5
  29. 54
  30. 8
  31. 1
  32. 72
  33. 6
  34. 9
  35. 5
  36. 9
  37. 6
  38. 4
  39. 7
  40. 4

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