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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 143 · 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.?832 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.27?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?519 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.124? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.7?44 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.66? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.8?76 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.236? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 28 and take away the sum of its digits. What do you get?
  10. 10.Take 88 and take away the sum of its digits. What do you get?
  11. 11.5?55 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 62 and take away the sum of its digits. What do you get?
  13. 13.4?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 71 and take away the sum of its digits. What do you get?
  15. 15.8?94 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 27 and take away the sum of its digits. What do you get?
  17. 17.Take 73 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.Take 19 and take away the sum of its digits. What do you get?
  20. 20.Take 70 and take away the sum of its digits. What do you get?
  21. 21.Take 98 and take away the sum of its digits. What do you get?
  22. 22.62?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?299 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?295 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.22?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?96 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 47 and take away the sum of its digits. What do you get?
  28. 28.2?76 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.?872 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 79 and take away the sum of its digits. What do you get?
  31. 31.17?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.15?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 68 and take away the sum of its digits. What do you get?
  34. 34.Take 43 and take away the sum of its digits. What do you get?
  35. 35.590? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 83 and take away the sum of its digits. What do you get?
  37. 37.Take 57 and take away the sum of its digits. What do you get?
  38. 38.Take 69 and take away the sum of its digits. What do you get?
  39. 39.?97 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?408 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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