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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 787 · 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.?431 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?285 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?750 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?300 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.726? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 87 and take away the sum of its digits. What do you get?
  7. 7.7?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?150 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.?655 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.23?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 46 and take away the sum of its digits. What do you get?
  12. 12.?588 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?381 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.217? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 90 and take away the sum of its digits. What do you get?
  16. 16.Take 56 and take away the sum of its digits. What do you get?
  17. 17.?602 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.?740 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.6?25 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.5?62 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 73 and take away the sum of its digits. What do you get?
  22. 22.Take 98 and take away the sum of its digits. What do you get?
  23. 23.1?66 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 47 and take away the sum of its digits. What do you get?
  25. 25.24?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.136? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.6?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.3?65 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 26 and take away the sum of its digits. What do you get?
  30. 30.Take 79 and take away the sum of its digits. What do you get?
  31. 31.Take 78 and take away the sum of its digits. What do you get?
  32. 32.Take 33 and take away the sum of its digits. What do you get?
  33. 33.37?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?028 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?100 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 72 and take away the sum of its digits. What do you get?
  37. 37.25?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.27?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.6?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 1
  2. 3
  3. 6
  4. 6
  5. 3
  6. 72
  7. 5
  8. 3
  9. 2
  10. 4
  11. 36
  12. 6
  13. 6
  14. 8
  15. 81
  16. 45
  17. 1
  18. 7
  19. 5
  20. 5
  21. 63
  22. 81
  23. 5
  24. 36
  25. 3
  26. 8
  27. 9
  28. 4
  29. 18
  30. 63
  31. 63
  32. 27
  33. 2
  34. 8
  35. 8
  36. 63
  37. 2
  38. 8
  39. 3
  40. 6

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