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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 841 · 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. 1.81² =
  2. 2.39² =
  3. 3.49² =
  4. 4.59² =
  5. 5.51² =
  6. 6.29² =
  7. 7.59² =
  8. 8.61² =
  9. 9.89² =
  10. 10.69² =
  11. 11.41² =
  12. 12.41² =
  13. 13.41² =
  14. 14.41² =
  15. 15.39² =
  16. 16.39² =
  17. 17.91² =
  18. 18.61² =
  19. 19.41² =
  20. 20.89² =
  21. 21.81² =
  22. 22.79² =
  23. 23.19² =
  24. 24.61² =
  25. 25.49² =
  26. 26.79² =
  27. 27.31² =
  28. 28.21² =
  29. 29.79² =
  30. 30.59² =
  31. 31.39² =
  32. 32.19² =
  33. 33.21² =
  34. 34.71² =
  35. 35.29² =
  36. 36.89² =
  37. 37.59² =
  38. 38.51² =
  39. 39.21² =
  40. 40.91² =

Answer key

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

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