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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 968 · 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. 1.12?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.175? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 54 and take away the sum of its digits. What do you get?
  4. 4.Take 23 and take away the sum of its digits. What do you get?
  5. 5.7?80 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.?646 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.4?99 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?605 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 76 and take away the sum of its digits. What do you get?
  10. 10.Take 17 and take away the sum of its digits. What do you get?
  11. 11.Take 69 and take away the sum of its digits. What do you get?
  12. 12.Take 15 and take away the sum of its digits. What do you get?
  13. 13.7?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 89 and take away the sum of its digits. What do you get?
  15. 15.72?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.30?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 87 and take away the sum of its digits. What do you get?
  18. 18.?034 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 63 and take away the sum of its digits. What do you get?
  20. 20.?070 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.530? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.7?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 36 and take away the sum of its digits. What do you get?
  24. 24.20?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.4?85 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.66?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.180? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.1?90 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. 30.1?10 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?625 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.5?63 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.5?97 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 37 and take away the sum of its digits. What do you get?
  35. 35.6?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.5?98 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.23?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 53 and take away the sum of its digits. What do you get?
  39. 39.?645 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.307? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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