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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 509 · 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.Take 96 and take away the sum of its digits. What do you get?
  2. 2.Take 14 and take away the sum of its digits. What do you get?
  3. 3.698? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.3?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.30?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 95 and take away the sum of its digits. What do you get?
  7. 7.?187 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.7?65 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?913 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.58?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?618 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.436? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.Take 51 and take away the sum of its digits. What do you get?
  14. 14.73?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?829 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.6?74 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 63 and take away the sum of its digits. What do you get?
  18. 18.Take 23 and take away the sum of its digits. What do you get?
  19. 19.Take 86 and take away the sum of its digits. What do you get?
  20. 20.?86 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.61? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.7?40 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 27 and take away the sum of its digits. What do you get?
  24. 24.2?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?056 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.348? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?778 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 62 and take away the sum of its digits. What do you get?
  29. 29.Take 66 and take away the sum of its digits. What do you get?
  30. 30.809? 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. 32.48? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.3?26 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.873? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.54?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?510 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?74 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 94 and take away the sum of its digits. What do you get?
  39. 39.37?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?183 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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