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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 18 · 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. 1.2?63 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 65 and take away the sum of its digits. What do you get?
  3. 3.2?96 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?807 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 45 and take away the sum of its digits. What do you get?
  6. 6.?442 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.21?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.40?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.15?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?942 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 91 and take away the sum of its digits. What do you get?
  12. 12.5?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 88 and take away the sum of its digits. What do you get?
  14. 14.72?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.2?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 58 and take away the sum of its digits. What do you get?
  17. 17.83? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.6?12 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?631 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.1?48 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.16?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 56 and take away the sum of its digits. What do you get?
  23. 23.?618 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 97 and take away the sum of its digits. What do you get?
  25. 25.Take 26 and take away the sum of its digits. What do you get?
  26. 26.Take 49 and take away the sum of its digits. What do you get?
  27. 27.467? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.?269 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 98 and take away the sum of its digits. What do you get?
  30. 30.?178 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.61?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?250 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.301? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 34 and take away the sum of its digits. What do you get?
  35. 35.191? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.46?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.1?85 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.247? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.53?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.893? 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. 54
  3. 1
  4. 3
  5. 36
  6. 8
  7. 2
  8. 5
  9. 3
  10. 3
  11. 81
  12. 9
  13. 72
  14. 7
  15. 5
  16. 45
  17. 7
  18. 9
  19. 8
  20. 5
  21. 9
  22. 45
  23. 3
  24. 81
  25. 18
  26. 36
  27. 1
  28. 1
  29. 81
  30. 2
  31. 9
  32. 2
  33. 5
  34. 27
  35. 7
  36. 8
  37. 4
  38. 5
  39. 5
  40. 7

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