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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 421 · 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. 1.51² =
  2. 2.41² =
  3. 3.89² =
  4. 4.89² =
  5. 5.81² =
  6. 6.71² =
  7. 7.31² =
  8. 8.51² =
  9. 9.21² =
  10. 10.19² =
  11. 11.71² =
  12. 12.41² =
  13. 13.71² =
  14. 14.31² =
  15. 15.31² =
  16. 16.79² =
  17. 17.39² =
  18. 18.91² =
  19. 19.79² =
  20. 20.61² =
  21. 21.89² =
  22. 22.51² =
  23. 23.49² =
  24. 24.79² =
  25. 25.21² =
  26. 26.29² =
  27. 27.49² =
  28. 28.29² =
  29. 29.21² =
  30. 30.69² =
  31. 31.49² =
  32. 32.69² =
  33. 33.61² =
  34. 34.59² =
  35. 35.89² =
  36. 36.39² =
  37. 37.49² =
  38. 38.79² =
  39. 39.51² =
  40. 40.61² =

Answer key

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

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