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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 182 · 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.?124 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?295 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.261? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.525? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 26 and take away the sum of its digits. What do you get?
  6. 6.?214 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.Take 90 and take away the sum of its digits. What do you get?
  8. 8.Take 86 and take away the sum of its digits. What do you get?
  9. 9.Take 21 and take away the sum of its digits. What do you get?
  10. 10.71?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?22 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.755? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.7?87 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.8?74 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 28 and take away the sum of its digits. What do you get?
  16. 16.463? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.7?25 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.Take 31 and take away the sum of its digits. What do you get?
  19. 19.?510 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.Take 91 and take away the sum of its digits. What do you get?
  21. 21.?448 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?121 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?758 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.?97 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.61?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.4?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.?187 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 54 and take away the sum of its digits. What do you get?
  29. 29.Take 25 and take away the sum of its digits. What do you get?
  30. 30.2?59 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.711? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?485 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 32 and take away the sum of its digits. What do you get?
  34. 34.Take 70 and take away the sum of its digits. What do you get?
  35. 35.737? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.Take 87 and take away the sum of its digits. What do you get?
  37. 37.17?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 58 and take away the sum of its digits. What do you get?
  39. 39.8?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.623? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

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

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