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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 960 · 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.?410 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.9?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.4?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.35? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 12 and take away the sum of its digits. What do you get?
  6. 6.Take 28 and take away the sum of its digits. What do you get?
  7. 7.?058 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.592? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.5?24 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 23 and take away the sum of its digits. What do you get?
  11. 11.484? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?357 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 15 and take away the sum of its digits. What do you get?
  14. 14.?301 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?845 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.2?38 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 94 and take away the sum of its digits. What do you get?
  19. 19.Take 19 and take away the sum of its digits. What do you get?
  20. 20.?340 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.528? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 56 and take away the sum of its digits. What do you get?
  23. 23.?647 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 59 and take away the sum of its digits. What do you get?
  25. 25.?600 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.131? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?157 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.8?53 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 50 and take away the sum of its digits. What do you get?
  30. 30.435? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 62 and take away the sum of its digits. What do you get?
  32. 32.Take 18 and take away the sum of its digits. What do you get?
  33. 33.Take 35 and take away the sum of its digits. What do you get?
  34. 34.Take 49 and take away the sum of its digits. What do you get?
  35. 35.5?05 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 88 and take away the sum of its digits. What do you get?
  37. 37.Take 86 and take away the sum of its digits. What do you get?
  38. 38.429? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?375 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.4?04 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. 2
  3. 4
  4. 1
  5. 9
  6. 18
  7. 5
  8. 2
  9. 7
  10. 18
  11. 2
  12. 3
  13. 9
  14. 5
  15. 1
  16. 6
  17. 5
  18. 81
  19. 9
  20. 2
  21. 3
  22. 45
  23. 1
  24. 45
  25. 3
  26. 4
  27. 5
  28. 2
  29. 45
  30. 6
  31. 54
  32. 9
  33. 27
  34. 36
  35. 8
  36. 72
  37. 72
  38. 3
  39. 3
  40. 1

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