← Digit-sum magic lesson New set →

Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 406 · 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 77 and take away the sum of its digits. What do you get?
  2. 2.2?24 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  3. 3.23?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.Take 88 and take away the sum of its digits. What do you get?
  5. 5.75?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  6. 6.188? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.18?5 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.?978 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.7?78 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  10. 10.Take 98 and take away the sum of its digits. What do you get?
  11. 11.?29 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.140? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.70?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.14?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.3?03 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 78 and take away the sum of its digits. What do you get?
  17. 17.89?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  18. 18.49?8 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.?073 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  20. 20.826? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?852 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.?282 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?006 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.Take 72 and take away the sum of its digits. What do you get?
  25. 25.430? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  26. 26.?30 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  27. 27.Take 62 and take away the sum of its digits. What do you get?
  28. 28.578? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  29. 29.Take 11 and take away the sum of its digits. What do you get?
  30. 30.Take 26 and take away the sum of its digits. What do you get?
  31. 31.83?3 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?055 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.87?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.Take 20 and take away the sum of its digits. What do you get?
  35. 35.Take 93 and take away the sum of its digits. What do you get?
  36. 36.6?09 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.?050 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  39. 39.?003 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.Take 55 and take away the sum of its digits. What do you get?

Answer key

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

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