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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 911 · 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. 1.31² =
  2. 2.51² =
  3. 3.31² =
  4. 4.21² =
  5. 5.61² =
  6. 6.71² =
  7. 7.39² =
  8. 8.61² =
  9. 9.61² =
  10. 10.21² =
  11. 11.91² =
  12. 12.89² =
  13. 13.71² =
  14. 14.89² =
  15. 15.51² =
  16. 16.41² =
  17. 17.19² =
  18. 18.19² =
  19. 19.81² =
  20. 20.71² =
  21. 21.91² =
  22. 22.51² =
  23. 23.19² =
  24. 24.61² =
  25. 25.19² =
  26. 26.41² =
  27. 27.91² =
  28. 28.29² =
  29. 29.39² =
  30. 30.31² =
  31. 31.89² =
  32. 32.59² =
  33. 33.31² =
  34. 34.69² =
  35. 35.31² =
  36. 36.59² =
  37. 37.39² =
  38. 38.81² =
  39. 39.91² =
  40. 40.21² =

Answer key

  1. 961
  2. 2601
  3. 961
  4. 441
  5. 3721
  6. 5041
  7. 1521
  8. 3721
  9. 3721
  10. 441
  11. 8281
  12. 7921
  13. 5041
  14. 7921
  15. 2601
  16. 1681
  17. 361
  18. 361
  19. 6561
  20. 5041
  21. 8281
  22. 2601
  23. 361
  24. 3721
  25. 361
  26. 1681
  27. 8281
  28. 841
  29. 1521
  30. 961
  31. 7921
  32. 3481
  33. 961
  34. 4761
  35. 961
  36. 3481
  37. 1521
  38. 6561
  39. 8281
  40. 441

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