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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 908 · 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. 1.688? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?191 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?734 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 12 and take away the sum of its digits. What do you get?
  5. 5.?370 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.65?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?626 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?511 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 21 and take away the sum of its digits. What do you get?
  10. 10.?36 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 80 and take away the sum of its digits. What do you get?
  12. 12.?700 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 29 and take away the sum of its digits. What do you get?
  14. 14.Take 59 and take away the sum of its digits. What do you get?
  15. 15.?634 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.?173 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 23 and take away the sum of its digits. What do you get?
  18. 18.Take 19 and take away the sum of its digits. What do you get?
  19. 19.Take 74 and take away the sum of its digits. What do you get?
  20. 20.248? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 92 and take away the sum of its digits. What do you get?
  22. 22.Take 99 and take away the sum of its digits. What do you get?
  23. 23.Take 45 and take away the sum of its digits. What do you get?
  24. 24.Take 91 and take away the sum of its digits. What do you get?
  25. 25.8?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.70?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?604 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.35?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.485? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.751? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 71 and take away the sum of its digits. What do you get?
  32. 32.Take 25 and take away the sum of its digits. What do you get?
  33. 33.644? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 46 and take away the sum of its digits. What do you get?
  35. 35.4?37 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?447 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 70 and take away the sum of its digits. What do you get?
  38. 38.?82 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.2?73 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.812? 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. 7
  3. 4
  4. 9
  5. 8
  6. 5
  7. 4
  8. 2
  9. 18
  10. 9
  11. 72
  12. 2
  13. 18
  14. 45
  15. 5
  16. 7
  17. 18
  18. 9
  19. 63
  20. 4
  21. 81
  22. 81
  23. 36
  24. 81
  25. 9
  26. 4
  27. 8
  28. 4
  29. 1
  30. 5
  31. 63
  32. 18
  33. 4
  34. 36
  35. 4
  36. 3
  37. 63
  38. 8
  39. 6
  40. 7

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