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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 71 · 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. 1.91² =
  2. 2.41² =
  3. 3.59² =
  4. 4.19² =
  5. 5.19² =
  6. 6.81² =
  7. 7.49² =
  8. 8.49² =
  9. 9.89² =
  10. 10.51² =
  11. 11.59² =
  12. 12.41² =
  13. 13.59² =
  14. 14.19² =
  15. 15.69² =
  16. 16.91² =
  17. 17.89² =
  18. 18.19² =
  19. 19.61² =
  20. 20.49² =
  21. 21.31² =
  22. 22.69² =
  23. 23.21² =
  24. 24.29² =
  25. 25.21² =
  26. 26.89² =
  27. 27.49² =
  28. 28.19² =
  29. 29.59² =
  30. 30.79² =
  31. 31.39² =
  32. 32.31² =
  33. 33.21² =
  34. 34.51² =
  35. 35.79² =
  36. 36.31² =
  37. 37.91² =
  38. 38.49² =
  39. 39.51² =
  40. 40.51² =

Answer key

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

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