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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 158 · 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. 1.326? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.793? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.456? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?393 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 60 and take away the sum of its digits. What do you get?
  6. 6.Take 61 and take away the sum of its digits. What do you get?
  7. 7.85?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?349 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.2?77 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 76 and take away the sum of its digits. What do you get?
  11. 11.60?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?007 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.203? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 86 and take away the sum of its digits. What do you get?
  15. 15.8?43 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.2?13 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.2?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 81 and take away the sum of its digits. What do you get?
  20. 20.Take 59 and take away the sum of its digits. What do you get?
  21. 21.750? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 96 and take away the sum of its digits. What do you get?
  23. 23.14?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.88?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?494 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.640? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.189? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?660 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.3?55 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 46 and take away the sum of its digits. What do you get?
  31. 31.Take 13 and take away the sum of its digits. What do you get?
  32. 32.25?3 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.Take 19 and take away the sum of its digits. What do you get?
  35. 35.8?76 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?544 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 43 and take away the sum of its digits. What do you get?
  38. 38.?818 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 18 and take away the sum of its digits. What do you get?
  40. 40.6?6 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. 8
  3. 3
  4. 3
  5. 54
  6. 54
  7. 2
  8. 2
  9. 2
  10. 63
  11. 2
  12. 2
  13. 4
  14. 72
  15. 3
  16. 3
  17. 8
  18. 3
  19. 72
  20. 45
  21. 6
  22. 81
  23. 7
  24. 4
  25. 1
  26. 8
  27. 9
  28. 6
  29. 5
  30. 36
  31. 9
  32. 8
  33. 72
  34. 9
  35. 6
  36. 5
  37. 36
  38. 1
  39. 9
  40. 6

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