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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 480 · 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.?767 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 86 and take away the sum of its digits. What do you get?
  3. 3.1?95 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.82?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 15 and take away the sum of its digits. What do you get?
  6. 6.130? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?978 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.2?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 87 and take away the sum of its digits. What do you get?
  10. 10.Take 57 and take away the sum of its digits. What do you get?
  11. 11.157? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.25?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?950 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?084 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.4?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 78 and take away the sum of its digits. What do you get?
  17. 17.?035 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 34 and take away the sum of its digits. What do you get?
  19. 19.Take 48 and take away the sum of its digits. What do you get?
  20. 20.Take 12 and take away the sum of its digits. What do you get?
  21. 21.22?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 73 and take away the sum of its digits. What do you get?
  23. 23.?127 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 68 and take away the sum of its digits. What do you get?
  25. 25.?125 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 83 and take away the sum of its digits. What do you get?
  27. 27.Take 84 and take away the sum of its digits. What do you get?
  28. 28.60?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?572 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.399? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.8?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 30 and take away the sum of its digits. What do you get?
  33. 33.?564 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.780? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?208 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.7?00 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 71 and take away the sum of its digits. What do you get?
  38. 38.Take 20 and take away the sum of its digits. What do you get?
  39. 39.Take 18 and take away the sum of its digits. What do you get?
  40. 40.5?45 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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