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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 665 · 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. 1.41² =
  2. 2.59² =
  3. 3.29² =
  4. 4.71² =
  5. 5.61² =
  6. 6.89² =
  7. 7.81² =
  8. 8.41² =
  9. 9.19² =
  10. 10.69² =
  11. 11.69² =
  12. 12.39² =
  13. 13.89² =
  14. 14.51² =
  15. 15.29² =
  16. 16.21² =
  17. 17.71² =
  18. 18.21² =
  19. 19.61² =
  20. 20.71² =
  21. 21.39² =
  22. 22.71² =
  23. 23.19² =
  24. 24.81² =
  25. 25.71² =
  26. 26.19² =
  27. 27.79² =
  28. 28.91² =
  29. 29.91² =
  30. 30.71² =
  31. 31.31² =
  32. 32.41² =
  33. 33.69² =
  34. 34.41² =
  35. 35.91² =
  36. 36.81² =
  37. 37.49² =
  38. 38.79² =
  39. 39.29² =
  40. 40.21² =

Answer key

  1. 1681
  2. 3481
  3. 841
  4. 5041
  5. 3721
  6. 7921
  7. 6561
  8. 1681
  9. 361
  10. 4761
  11. 4761
  12. 1521
  13. 7921
  14. 2601
  15. 841
  16. 441
  17. 5041
  18. 441
  19. 3721
  20. 5041
  21. 1521
  22. 5041
  23. 361
  24. 6561
  25. 5041
  26. 361
  27. 6241
  28. 8281
  29. 8281
  30. 5041
  31. 961
  32. 1681
  33. 4761
  34. 1681
  35. 8281
  36. 6561
  37. 2401
  38. 6241
  39. 841
  40. 441

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