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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 79 · 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. 1.89² =
  2. 2.29² =
  3. 3.59² =
  4. 4.61² =
  5. 5.59² =
  6. 6.29² =
  7. 7.69² =
  8. 8.49² =
  9. 9.41² =
  10. 10.29² =
  11. 11.29² =
  12. 12.69² =
  13. 13.61² =
  14. 14.69² =
  15. 15.39² =
  16. 16.79² =
  17. 17.31² =
  18. 18.19² =
  19. 19.41² =
  20. 20.31² =
  21. 21.81² =
  22. 22.69² =
  23. 23.79² =
  24. 24.89² =
  25. 25.39² =
  26. 26.79² =
  27. 27.39² =
  28. 28.29² =
  29. 29.51² =
  30. 30.31² =
  31. 31.69² =
  32. 32.89² =
  33. 33.71² =
  34. 34.21² =
  35. 35.91² =
  36. 36.89² =
  37. 37.51² =
  38. 38.51² =
  39. 39.39² =
  40. 40.71² =

Answer key

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

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