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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 264 · 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 67 and take away the sum of its digits. What do you get?
  2. 2.Take 92 and take away the sum of its digits. What do you get?
  3. 3.Take 21 and take away the sum of its digits. What do you get?
  4. 4.Take 57 and take away the sum of its digits. What do you get?
  5. 5.351? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.27?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.2?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 49 and take away the sum of its digits. What do you get?
  9. 9.2?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.37?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.78? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 74 and take away the sum of its digits. What do you get?
  13. 13.81?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.627? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?804 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.1?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 61 and take away the sum of its digits. What do you get?
  18. 18.Take 88 and take away the sum of its digits. What do you get?
  19. 19.11?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.769? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 37 and take away the sum of its digits. What do you get?
  22. 22.Take 13 and take away the sum of its digits. What do you get?
  23. 23.10?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 29 and take away the sum of its digits. What do you get?
  25. 25.4?47 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 78 and take away the sum of its digits. What do you get?
  27. 27.7?69 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.109? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 11 and take away the sum of its digits. What do you get?
  30. 30.75?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.217? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?066 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.31?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.671? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.29?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 51 and take away the sum of its digits. What do you get?
  37. 37.64?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.395? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.863? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.210? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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