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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 148 · 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. 3.21² =
  4. 4.31² =
  5. 5.69² =
  6. 6.79² =
  7. 7.41² =
  8. 8.29² =
  9. 9.29² =
  10. 10.79² =
  11. 11.49² =
  12. 12.21² =
  13. 13.71² =
  14. 14.69² =
  15. 15.39² =
  16. 16.81² =
  17. 17.19² =
  18. 18.21² =
  19. 19.39² =
  20. 20.69² =
  21. 21.31² =
  22. 22.21² =
  23. 23.19² =
  24. 24.71² =
  25. 25.51² =
  26. 26.69² =
  27. 27.19² =
  28. 28.29² =
  29. 29.19² =
  30. 30.71² =
  31. 31.71² =
  32. 32.29² =
  33. 33.61² =
  34. 34.61² =
  35. 35.39² =
  36. 36.81² =
  37. 37.71² =
  38. 38.69² =
  39. 39.59² =
  40. 40.49² =

Answer key

  1. 2601
  2. 841
  3. 441
  4. 961
  5. 4761
  6. 6241
  7. 1681
  8. 841
  9. 841
  10. 6241
  11. 2401
  12. 441
  13. 5041
  14. 4761
  15. 1521
  16. 6561
  17. 361
  18. 441
  19. 1521
  20. 4761
  21. 961
  22. 441
  23. 361
  24. 5041
  25. 2601
  26. 4761
  27. 361
  28. 841
  29. 361
  30. 5041
  31. 5041
  32. 841
  33. 3721
  34. 3721
  35. 1521
  36. 6561
  37. 5041
  38. 4761
  39. 3481
  40. 2401

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