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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 370 · 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 31 and take away the sum of its digits. What do you get?
  2. 2.?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?79 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.2?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.4?80 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?168 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.371? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?384 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.4?36 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 64 and take away the sum of its digits. What do you get?
  11. 11.?786 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.42?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?940 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.8?16 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 88 and take away the sum of its digits. What do you get?
  16. 16.Take 83 and take away the sum of its digits. What do you get?
  17. 17.Take 34 and take away the sum of its digits. What do you get?
  18. 18.?386 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 38 and take away the sum of its digits. What do you get?
  20. 20.?668 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 23 and take away the sum of its digits. What do you get?
  22. 22.Take 56 and take away the sum of its digits. What do you get?
  23. 23.42?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.4?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.555? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 25 and take away the sum of its digits. What do you get?
  27. 27.Take 18 and take away the sum of its digits. What do you get?
  28. 28.2?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?955 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?507 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 20 and take away the sum of its digits. What do you get?
  32. 32.Take 59 and take away the sum of its digits. What do you get?
  33. 33.24?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.1?94 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. 36.29?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.7?41 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 30 and take away the sum of its digits. What do you get?
  39. 39.Take 79 and take away the sum of its digits. What do you get?
  40. 40.5?35 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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