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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 141 · 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. 1.779? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.862? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 55 and take away the sum of its digits. What do you get?
  4. 4.6?41 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. 6.67? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?409 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.543? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.80?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.47?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 29 and take away the sum of its digits. What do you get?
  12. 12.?400 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 98 and take away the sum of its digits. What do you get?
  14. 14.Take 25 and take away the sum of its digits. What do you get?
  15. 15.Take 54 and take away the sum of its digits. What do you get?
  16. 16.?761 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.58?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 18 and take away the sum of its digits. What do you get?
  19. 19.?607 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.62?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.1?51 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 31 and take away the sum of its digits. What do you get?
  23. 23.1?26 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 74 and take away the sum of its digits. What do you get?
  25. 25.?36 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 77 and take away the sum of its digits. What do you get?
  27. 27.2?45 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.638? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.893? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 60 and take away the sum of its digits. What do you get?
  31. 31.Take 52 and take away the sum of its digits. What do you get?
  32. 32.5?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.11?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.9?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 27 and take away the sum of its digits. What do you get?
  36. 36.?974 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.17?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.3?97 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 53 and take away the sum of its digits. What do you get?
  40. 40.6?1 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. 45
  4. 7
  5. 27
  6. 5
  7. 5
  8. 6
  9. 4
  10. 1
  11. 18
  12. 5
  13. 81
  14. 18
  15. 45
  16. 4
  17. 5
  18. 9
  19. 5
  20. 7
  21. 2
  22. 27
  23. 9
  24. 63
  25. 9
  26. 63
  27. 7
  28. 1
  29. 7
  30. 54
  31. 45
  32. 1
  33. 6
  34. 7
  35. 18
  36. 7
  37. 8
  38. 8
  39. 45
  40. 2

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