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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 827 · 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.?716 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?723 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.1?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 53 and take away the sum of its digits. What do you get?
  5. 5.Take 63 and take away the sum of its digits. What do you get?
  6. 6.80?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.201? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.Take 58 and take away the sum of its digits. What do you get?
  9. 9.Take 46 and take away the sum of its digits. What do you get?
  10. 10.4?32 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.6?20 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.Take 21 and take away the sum of its digits. What do you get?
  13. 13.Take 79 and take away the sum of its digits. What do you get?
  14. 14.Take 40 and take away the sum of its digits. What do you get?
  15. 15.?133 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 55 and take away the sum of its digits. What do you get?
  17. 17.Take 33 and take away the sum of its digits. What do you get?
  18. 18.Take 71 and take away the sum of its digits. What do you get?
  19. 19.?50 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 36 and take away the sum of its digits. What do you get?
  21. 21.30?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.Take 76 and take away the sum of its digits. What do you get?
  23. 23.?859 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 65 and take away the sum of its digits. What do you get?
  25. 25.24?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.42?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.697? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.58?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.3?08 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.Take 92 and take away the sum of its digits. What do you get?
  31. 31.Take 74 and take away the sum of its digits. What do you get?
  32. 32.79?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.22?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.756? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?906 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.3?60 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 31 and take away the sum of its digits. What do you get?
  38. 38.777? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 54 and take away the sum of its digits. What do you get?
  40. 40.20?7 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. 6
  3. 2
  4. 45
  5. 54
  6. 5
  7. 6
  8. 45
  9. 36
  10. 9
  11. 1
  12. 18
  13. 63
  14. 36
  15. 2
  16. 45
  17. 27
  18. 63
  19. 4
  20. 27
  21. 8
  22. 63
  23. 5
  24. 54
  25. 2
  26. 3
  27. 5
  28. 5
  29. 7
  30. 81
  31. 63
  32. 5
  33. 5
  34. 9
  35. 3
  36. 9
  37. 27
  38. 6
  39. 45
  40. 9

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