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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 557 · 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.?059 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.528? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 49 and take away the sum of its digits. What do you get?
  4. 4.63?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 83 and take away the sum of its digits. What do you get?
  6. 6.Take 46 and take away the sum of its digits. What do you get?
  7. 7.82?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.816? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 48 and take away the sum of its digits. What do you get?
  10. 10.88?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.87?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.?788 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.57?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 60 and take away the sum of its digits. What do you get?
  15. 15.?673 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 85 and take away the sum of its digits. What do you get?
  17. 17.?879 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.354? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.57?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?251 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.78?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.8?53 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?690 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?065 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.Take 35 and take away the sum of its digits. What do you get?
  27. 27.Take 94 and take away the sum of its digits. What do you get?
  28. 28.?804 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.540? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.238? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 42 and take away the sum of its digits. What do you get?
  32. 32.419? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.643? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.6?45 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.Take 36 and take away the sum of its digits. What do you get?
  36. 36.Take 44 and take away the sum of its digits. What do you get?
  37. 37.Take 20 and take away the sum of its digits. What do you get?
  38. 38.Take 82 and take away the sum of its digits. What do you get?
  39. 39.14?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?839 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. 3
  3. 36
  4. 3
  5. 72
  6. 36
  7. 8
  8. 3
  9. 36
  10. 7
  11. 3
  12. 4
  13. 3
  14. 54
  15. 2
  16. 72
  17. 3
  18. 6
  19. 4
  20. 8
  21. 1
  22. 7
  23. 2
  24. 3
  25. 7
  26. 27
  27. 81
  28. 6
  29. 9
  30. 5
  31. 36
  32. 4
  33. 5
  34. 3
  35. 27
  36. 36
  37. 18
  38. 72
  39. 4
  40. 7

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