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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 377 · 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.?905 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 62 and take away the sum of its digits. What do you get?
  3. 3.Take 34 and take away the sum of its digits. What do you get?
  4. 4.Take 26 and take away the sum of its digits. What do you get?
  5. 5.73? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 85 and take away the sum of its digits. What do you get?
  7. 7.751? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 30 and take away the sum of its digits. What do you get?
  9. 9.?416 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?21 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.41?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.5?55 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 28 and take away the sum of its digits. What do you get?
  14. 14.527? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?087 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 87 and take away the sum of its digits. What do you get?
  17. 17.Take 79 and take away the sum of its digits. What do you get?
  18. 18.?210 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.26?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 51 and take away the sum of its digits. What do you get?
  21. 21.Take 57 and take away the sum of its digits. What do you get?
  22. 22.?142 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?638 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?381 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 55 and take away the sum of its digits. What do you get?
  26. 26.Take 53 and take away the sum of its digits. What do you get?
  27. 27.Take 74 and take away the sum of its digits. What do you get?
  28. 28.Take 41 and take away the sum of its digits. What do you get?
  29. 29.?572 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.863? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?943 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?987 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.8?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 75 and take away the sum of its digits. What do you get?
  35. 35.83?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 64 and take away the sum of its digits. What do you get?
  37. 37.?88 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?199 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?272 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.764? 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. 54
  3. 27
  4. 18
  5. 8
  6. 72
  7. 5
  8. 27
  9. 7
  10. 6
  11. 8
  12. 3
  13. 18
  14. 4
  15. 3
  16. 72
  17. 63
  18. 6
  19. 3
  20. 45
  21. 45
  22. 2
  23. 1
  24. 6
  25. 45
  26. 45
  27. 63
  28. 36
  29. 4
  30. 1
  31. 2
  32. 3
  33. 7
  34. 63
  35. 6
  36. 54
  37. 2
  38. 8
  39. 7
  40. 1

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