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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 682 · 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 47 and take away the sum of its digits. What do you get?
  2. 2.?854 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.?813 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 69 and take away the sum of its digits. What do you get?
  5. 5.Take 70 and take away the sum of its digits. What do you get?
  6. 6.?02 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 45 and take away the sum of its digits. What do you get?
  8. 8.?030 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.6?54 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 62 and take away the sum of its digits. What do you get?
  11. 11.Take 22 and take away the sum of its digits. What do you get?
  12. 12.Take 17 and take away the sum of its digits. What do you get?
  13. 13.Take 39 and take away the sum of its digits. What do you get?
  14. 14.7?75 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?485 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 36 and take away the sum of its digits. What do you get?
  17. 17.?475 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 44 and take away the sum of its digits. What do you get?
  19. 19.71?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.24?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.1?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.85?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.19?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?320 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.722? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.169? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.41?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.57?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 28 and take away the sum of its digits. What do you get?
  30. 30.6?64 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.41?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.Take 42 and take away the sum of its digits. What do you get?
  33. 33.Take 20 and take away the sum of its digits. What do you get?
  34. 34.802? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.?192 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.?319 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.Take 66 and take away the sum of its digits. What do you get?
  38. 38.3?59 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.Take 26 and take away the sum of its digits. What do you get?
  40. 40.831? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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