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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 721 · 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. 1.19² =
  2. 2.51² =
  3. 3.71² =
  4. 4.49² =
  5. 5.59² =
  6. 6.29² =
  7. 7.51² =
  8. 8.69² =
  9. 9.49² =
  10. 10.89² =
  11. 11.61² =
  12. 12.89² =
  13. 13.41² =
  14. 14.79² =
  15. 15.21² =
  16. 16.61² =
  17. 17.71² =
  18. 18.31² =
  19. 19.21² =
  20. 20.69² =
  21. 21.51² =
  22. 22.49² =
  23. 23.59² =
  24. 24.39² =
  25. 25.49² =
  26. 26.19² =
  27. 27.21² =
  28. 28.61² =
  29. 29.89² =
  30. 30.29² =
  31. 31.39² =
  32. 32.39² =
  33. 33.69² =
  34. 34.89² =
  35. 35.29² =
  36. 36.19² =
  37. 37.41² =
  38. 38.29² =
  39. 39.89² =
  40. 40.19² =

Answer key

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

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