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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 846 · 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 73 and take away the sum of its digits. What do you get?
  2. 2.Take 53 and take away the sum of its digits. What do you get?
  3. 3.?213 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.45?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 82 and take away the sum of its digits. What do you get?
  6. 6.Take 84 and take away the sum of its digits. What do you get?
  7. 7.661? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.21?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.735? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.2?36 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 88 and take away the sum of its digits. What do you get?
  12. 12.?188 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.29?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?816 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 45 and take away the sum of its digits. What do you get?
  16. 16.Take 12 and take away the sum of its digits. What do you get?
  17. 17.Take 13 and take away the sum of its digits. What do you get?
  18. 18.Take 93 and take away the sum of its digits. What do you get?
  19. 19.252? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 69 and take away the sum of its digits. What do you get?
  21. 21.?118 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 67 and take away the sum of its digits. What do you get?
  23. 23.Take 35 and take away the sum of its digits. What do you get?
  24. 24.33? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 37 and take away the sum of its digits. What do you get?
  26. 26.?649 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?379 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?245 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?714 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?489 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.62?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?071 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 99 and take away the sum of its digits. What do you get?
  34. 34.6?98 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 49 and take away the sum of its digits. What do you get?
  36. 36.?169 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.204? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.8?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.8?31 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.52?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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