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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 148 · 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. 1.39?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.278? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.860? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 74 and take away the sum of its digits. What do you get?
  5. 5.Take 58 and take away the sum of its digits. What do you get?
  6. 6.Take 71 and take away the sum of its digits. What do you get?
  7. 7.797? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 53 and take away the sum of its digits. What do you get?
  9. 9.Take 83 and take away the sum of its digits. What do you get?
  10. 10.874? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 82 and take away the sum of its digits. What do you get?
  12. 12.Take 55 and take away the sum of its digits. What do you get?
  13. 13.65?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?170 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.5?19 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.26?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 86 and take away the sum of its digits. What do you get?
  18. 18.23?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.824? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?480 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.7?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.81?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 97 and take away the sum of its digits. What do you get?
  24. 24.8?89 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.74?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 23 and take away the sum of its digits. What do you get?
  27. 27.85?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 68 and take away the sum of its digits. What do you get?
  29. 29.?667 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.106? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?165 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.705? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 87 and take away the sum of its digits. What do you get?
  34. 34.?536 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 41 and take away the sum of its digits. What do you get?
  36. 36.?006 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 72 and take away the sum of its digits. What do you get?
  38. 38.Take 31 and take away the sum of its digits. What do you get?
  39. 39.Take 17 and take away the sum of its digits. What do you get?
  40. 40.3?52 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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