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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 964 · 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. 1.1?26 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?321 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.45?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 29 and take away the sum of its digits. What do you get?
  5. 5.Take 94 and take away the sum of its digits. What do you get?
  6. 6.569? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?438 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.4?70 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.59?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.1?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 44 and take away the sum of its digits. What do you get?
  12. 12.Take 12 and take away the sum of its digits. What do you get?
  13. 13.?712 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.?737 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.34?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.725? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.67?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 65 and take away the sum of its digits. What do you get?
  19. 19.Take 92 and take away the sum of its digits. What do you get?
  20. 20.?550 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.702? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?082 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?843 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 73 and take away the sum of its digits. What do you get?
  25. 25.3?65 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.1?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?526 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.7?14 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 70 and take away the sum of its digits. What do you get?
  30. 30.Take 97 and take away the sum of its digits. What do you get?
  31. 31.392? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.1?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.7?42 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.88?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?931 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.344? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?425 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 76 and take away the sum of its digits. What do you get?
  39. 39.Take 32 and take away the sum of its digits. What do you get?
  40. 40.Take 81 and take away the sum of its digits. What do you get?

Answer key

  1. 9
  2. 3
  3. 3
  4. 18
  5. 81
  6. 7
  7. 3
  8. 7
  9. 4
  10. 4
  11. 36
  12. 9
  13. 8
  14. 1
  15. 1
  16. 4
  17. 4
  18. 54
  19. 81
  20. 8
  21. 9
  22. 8
  23. 3
  24. 63
  25. 4
  26. 8
  27. 5
  28. 6
  29. 63
  30. 81
  31. 4
  32. 5
  33. 5
  34. 4
  35. 5
  36. 7
  37. 7
  38. 63
  39. 27
  40. 72

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