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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 500 · 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.Take 88 and take away the sum of its digits. What do you get?
  2. 2.842? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.198? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.70? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.?308 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.7?33 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.284? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.4?87 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.14?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.2?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 37 and take away the sum of its digits. What do you get?
  12. 12.48?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.1?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.37?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 80 and take away the sum of its digits. What do you get?
  16. 16.366? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.1?51 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.2?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 77 and take away the sum of its digits. What do you get?
  20. 20.14?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 64 and take away the sum of its digits. What do you get?
  22. 22.Take 68 and take away the sum of its digits. What do you get?
  23. 23.?199 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.199? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.319? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 57 and take away the sum of its digits. What do you get?
  27. 27.55?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?13 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?093 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?571 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?014 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 84 and take away the sum of its digits. What do you get?
  34. 34.Take 70 and take away the sum of its digits. What do you get?
  35. 35.Take 89 and take away the sum of its digits. What do you get?
  36. 36.Take 13 and take away the sum of its digits. What do you get?
  37. 37.259? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.3?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 21 and take away the sum of its digits. What do you get?
  40. 40.27?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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