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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 168 · 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.?053 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.7?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 59 and take away the sum of its digits. What do you get?
  4. 4.834? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.79?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 65 and take away the sum of its digits. What do you get?
  7. 7.Take 56 and take away the sum of its digits. What do you get?
  8. 8.62?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.88?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.11?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 15 and take away the sum of its digits. What do you get?
  12. 12.?566 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.832? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 11 and take away the sum of its digits. What do you get?
  16. 16.333? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 45 and take away the sum of its digits. What do you get?
  18. 18.Take 92 and take away the sum of its digits. What do you get?
  19. 19.191? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?541 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?34 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.687? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?223 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.5?92 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.1?39 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?494 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.715? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.3?90 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 96 and take away the sum of its digits. What do you get?
  30. 30.Take 28 and take away the sum of its digits. What do you get?
  31. 31.Take 35 and take away the sum of its digits. What do you get?
  32. 32.Take 62 and take away the sum of its digits. What do you get?
  33. 33.Take 57 and take away the sum of its digits. What do you get?
  34. 34.Take 97 and take away the sum of its digits. What do you get?
  35. 35.Take 88 and take away the sum of its digits. What do you get?
  36. 36.699? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.242? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.531? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?386 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?33 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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