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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 862 · 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 82 and take away the sum of its digits. What do you get?
  2. 2.60?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.80?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.35?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 34 and take away the sum of its digits. What do you get?
  6. 6.7?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 59 and take away the sum of its digits. What do you get?
  8. 8.?575 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.470? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 53 and take away the sum of its digits. What do you get?
  11. 11.Take 35 and take away the sum of its digits. What do you get?
  12. 12.Take 74 and take away the sum of its digits. What do you get?
  13. 13.64?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 11 and take away the sum of its digits. What do you get?
  15. 15.?490 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 73 and take away the sum of its digits. What do you get?
  17. 17.4?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?307 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.6?91 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 52 and take away the sum of its digits. What do you get?
  21. 21.19?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?102 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.23?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 58 and take away the sum of its digits. What do you get?
  25. 25.?985 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 93 and take away the sum of its digits. What do you get?
  27. 27.?710 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.3?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.40?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.199? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 78 and take away the sum of its digits. What do you get?
  32. 32.890? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.?647 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 16 and take away the sum of its digits. What do you get?
  35. 35.3?17 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 15 and take away the sum of its digits. What do you get?
  37. 37.346? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 17 and take away the sum of its digits. What do you get?
  39. 39.6?12 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?438 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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