← Digit-sum magic lesson New set →

Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 193 · 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 99 and take away the sum of its digits. What do you get?
  2. 2.Take 28 and take away the sum of its digits. What do you get?
  3. 3.Take 97 and take away the sum of its digits. What do you get?
  4. 4.Take 93 and take away the sum of its digits. What do you get?
  5. 5.82?0 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. 7.178? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?722 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.32?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.?724 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.878? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.45?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.?012 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.Take 30 and take away the sum of its digits. What do you get?
  15. 15.60? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.19?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  17. 17.?957 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.6?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.156? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.5?26 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.Take 56 and take away the sum of its digits. What do you get?
  22. 22.600? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.Take 83 and take away the sum of its digits. What do you get?
  24. 24.46?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.?727 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.197? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.795? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.14?0 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.19?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  30. 30.?910 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  31. 31.Take 11 and take away the sum of its digits. What do you get?
  32. 32.44?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.817? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?367 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.63?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.8?7 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?816 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.?401 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.8?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 33 and take away the sum of its digits. What do you get?

Answer key

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

Free maths tricks lessons, practice and worksheets at talentjr.in/maths-tricks