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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 886 · 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. 1.401? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.81? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?600 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.7?18 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 31 and take away the sum of its digits. What do you get?
  6. 6.2?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?538 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.6?24 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?716 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?546 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.369? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?949 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 20 and take away the sum of its digits. What do you get?
  14. 14.6?01 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?013 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 88 and take away the sum of its digits. What do you get?
  17. 17.Take 68 and take away the sum of its digits. What do you get?
  18. 18.6?26 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 70 and take away the sum of its digits. What do you get?
  20. 20.?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 34 and take away the sum of its digits. What do you get?
  22. 22.Take 78 and take away the sum of its digits. What do you get?
  23. 23.Take 63 and take away the sum of its digits. What do you get?
  24. 24.Take 57 and take away the sum of its digits. What do you get?
  25. 25.72?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.4?15 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?778 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  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.?883 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 49 and take away the sum of its digits. What do you get?
  31. 31.463? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?145 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 37 and take away the sum of its digits. What do you get?
  34. 34.1?09 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.24?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?660 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.477? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 97 and take away the sum of its digits. What do you get?
  39. 39.740? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.424? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 4
  2. 9
  3. 3
  4. 2
  5. 27
  6. 7
  7. 2
  8. 6
  9. 4
  10. 3
  11. 9
  12. 5
  13. 18
  14. 2
  15. 5
  16. 72
  17. 54
  18. 4
  19. 63
  20. 6
  21. 27
  22. 63
  23. 54
  24. 45
  25. 9
  26. 8
  27. 5
  28. 3
  29. 8
  30. 36
  31. 5
  32. 8
  33. 27
  34. 8
  35. 5
  36. 6
  37. 9
  38. 81
  39. 7
  40. 8

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