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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 456 · 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 64 and take away the sum of its digits. What do you get?
  2. 2.Take 87 and take away the sum of its digits. What do you get?
  3. 3.2?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.897? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.33?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 93 and take away the sum of its digits. What do you get?
  7. 7.?435 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?560 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.100? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?272 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.49?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?964 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 42 and take away the sum of its digits. What do you get?
  14. 14.Take 12 and take away the sum of its digits. What do you get?
  15. 15.?074 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.89?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.124? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 22 and take away the sum of its digits. What do you get?
  19. 19.34?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 39 and take away the sum of its digits. What do you get?
  21. 21.738? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.67?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 15 and take away the sum of its digits. What do you get?
  24. 24.?28 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 16 and take away the sum of its digits. What do you get?
  26. 26.?055 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 84 and take away the sum of its digits. What do you get?
  28. 28.8?65 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?179 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.50?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.2?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 79 and take away the sum of its digits. What do you get?
  33. 33.5?80 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.8?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 99 and take away the sum of its digits. What do you get?
  36. 36.?316 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 46 and take away the sum of its digits. What do you get?
  38. 38.?213 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?210 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 76 and take away the sum of its digits. What do you get?

Answer key

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

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