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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 514 · 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. 1.7?97 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.Take 19 and take away the sum of its digits. What do you get?
  3. 3.?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.5?96 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 68 and take away the sum of its digits. What do you get?
  6. 6.55?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?410 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?566 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.491? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.503? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.3?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 57 and take away the sum of its digits. What do you get?
  13. 13.7?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 64 and take away the sum of its digits. What do you get?
  15. 15.44? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.5?80 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 86 and take away the sum of its digits. What do you get?
  18. 18.?320 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.574? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 25 and take away the sum of its digits. What do you get?
  21. 21.2?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.567? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.155? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?608 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 88 and take away the sum of its digits. What do you get?
  26. 26.Take 47 and take away the sum of its digits. What do you get?
  27. 27.Take 58 and take away the sum of its digits. What do you get?
  28. 28.Take 34 and take away the sum of its digits. What do you get?
  29. 29.?142 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?98 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 20 and take away the sum of its digits. What do you get?
  32. 32.?006 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 35 and take away the sum of its digits. What do you get?
  34. 34.?830 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?973 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 32 and take away the sum of its digits. What do you get?
  37. 37.Take 98 and take away the sum of its digits. What do you get?
  38. 38.?357 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.71? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.5?47 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. 9
  3. 6
  4. 7
  5. 54
  6. 1
  7. 4
  8. 1
  9. 4
  10. 1
  11. 2
  12. 45
  13. 8
  14. 54
  15. 1
  16. 5
  17. 72
  18. 4
  19. 2
  20. 18
  21. 2
  22. 9
  23. 7
  24. 4
  25. 72
  26. 36
  27. 45
  28. 27
  29. 2
  30. 1
  31. 18
  32. 3
  33. 27
  34. 7
  35. 8
  36. 27
  37. 81
  38. 3
  39. 1
  40. 2

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