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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 682 · 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. 1.39² =
  2. 2.79² =
  3. 3.19² =
  4. 4.81² =
  5. 5.69² =
  6. 6.91² =
  7. 7.79² =
  8. 8.49² =
  9. 9.19² =
  10. 10.49² =
  11. 11.61² =
  12. 12.51² =
  13. 13.51² =
  14. 14.19² =
  15. 15.91² =
  16. 16.21² =
  17. 17.89² =
  18. 18.21² =
  19. 19.19² =
  20. 20.31² =
  21. 21.21² =
  22. 22.41² =
  23. 23.61² =
  24. 24.51² =
  25. 25.51² =
  26. 26.59² =
  27. 27.61² =
  28. 28.69² =
  29. 29.21² =
  30. 30.51² =
  31. 31.79² =
  32. 32.49² =
  33. 33.69² =
  34. 34.89² =
  35. 35.49² =
  36. 36.91² =
  37. 37.39² =
  38. 38.61² =
  39. 39.41² =
  40. 40.29² =

Answer key

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

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