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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 816 · 40 questions
TalentJR

The fast method (Step from a neighbour): Find the round neighbour and square it: 70² = 7 × 7 = 49, then two 0s → 4900. Ends in 1 (one more)? Add the round number and the number: 4900 + 70 + 71. Ends in 9 (one less)? Take them away: 69² = 4900 − 70 − 69 = 4761.

NameDateTime takenScore ___ / 40
  1. 1.51² =
  2. 2.29² =
  3. 3.69² =
  4. 4.19² =
  5. 5.29² =
  6. 6.71² =
  7. 7.81² =
  8. 8.79² =
  9. 9.49² =
  10. 10.19² =
  11. 11.79² =
  12. 12.31² =
  13. 13.71² =
  14. 14.19² =
  15. 15.69² =
  16. 16.39² =
  17. 17.81² =
  18. 18.89² =
  19. 19.41² =
  20. 20.71² =
  21. 21.49² =
  22. 22.49² =
  23. 23.19² =
  24. 24.39² =
  25. 25.89² =
  26. 26.31² =
  27. 27.31² =
  28. 28.31² =
  29. 29.51² =
  30. 30.79² =
  31. 31.19² =
  32. 32.49² =
  33. 33.81² =
  34. 34.69² =
  35. 35.69² =
  36. 36.31² =
  37. 37.81² =
  38. 38.79² =
  39. 39.69² =
  40. 40.49² =

Answer key

  1. 2601
  2. 841
  3. 4761
  4. 361
  5. 841
  6. 5041
  7. 6561
  8. 6241
  9. 2401
  10. 361
  11. 6241
  12. 961
  13. 5041
  14. 361
  15. 4761
  16. 1521
  17. 6561
  18. 7921
  19. 1681
  20. 5041
  21. 2401
  22. 2401
  23. 361
  24. 1521
  25. 7921
  26. 961
  27. 961
  28. 961
  29. 2601
  30. 6241
  31. 361
  32. 2401
  33. 6561
  34. 4761
  35. 4761
  36. 961
  37. 6561
  38. 6241
  39. 4761
  40. 2401

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