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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 468 · 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. 1.6?49 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.6?97 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.507? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 19 and take away the sum of its digits. What do you get?
  5. 5.?310 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.180? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.2?87 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.47?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.771? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 61 and take away the sum of its digits. What do you get?
  11. 11.Take 46 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. 13.64?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?89 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?109 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.210? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.60? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 31 and take away the sum of its digits. What do you get?
  19. 19.Take 92 and take away the sum of its digits. What do you get?
  20. 20.176? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 85 and take away the sum of its digits. What do you get?
  22. 22.3?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.5?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 42 and take away the sum of its digits. What do you get?
  25. 25.96? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 82 and take away the sum of its digits. What do you get?
  27. 27.3?67 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.61?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?534 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?664 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.20?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.25?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 78 and take away the sum of its digits. What do you get?
  34. 34.Take 56 and take away the sum of its digits. What do you get?
  35. 35.Take 22 and take away the sum of its digits. What do you get?
  36. 36.?832 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.5?49 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 25 and take away the sum of its digits. What do you get?
  39. 39.Take 34 and take away the sum of its digits. What do you get?
  40. 40.734? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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