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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 426 · 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.?164 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  2. 2.?27 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.Take 49 and take away the sum of its digits. What do you get?
  4. 4.?582 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.258? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.Take 73 and take away the sum of its digits. What do you get?
  7. 7.28?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?48 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.1?65 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?717 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.Take 35 and take away the sum of its digits. What do you get?
  12. 12.Take 43 and take away the sum of its digits. What do you get?
  13. 13.Take 97 and take away the sum of its digits. What do you get?
  14. 14.415? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.Take 78 and take away the sum of its digits. What do you get?
  16. 16.?284 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.Take 69 and take away the sum of its digits. What do you get?
  18. 18.Take 34 and take away the sum of its digits. What do you get?
  19. 19.6?46 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.?93 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?043 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?63 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?211 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 23 and take away the sum of its digits. What do you get?
  25. 25.1?47 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.3?04 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.24? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 86 and take away the sum of its digits. What do you get?
  29. 29.Take 58 and take away the sum of its digits. What do you get?
  30. 30.867? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.?688 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.84?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.Take 63 and take away the sum of its digits. What do you get?
  34. 34.Take 66 and take away the sum of its digits. What do you get?
  35. 35.71?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.72? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?433 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.1?32 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.3?53 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.?47 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 7
  2. 9
  3. 36
  4. 3
  5. 3
  6. 63
  7. 5
  8. 6
  9. 6
  10. 3
  11. 27
  12. 36
  13. 81
  14. 8
  15. 63
  16. 4
  17. 54
  18. 27
  19. 2
  20. 6
  21. 2
  22. 9
  23. 5
  24. 18
  25. 6
  26. 2
  27. 3
  28. 72
  29. 45
  30. 6
  31. 5
  32. 1
  33. 54
  34. 54
  35. 3
  36. 9
  37. 8
  38. 3
  39. 7
  40. 7

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