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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 729 · 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. 1.41² =
  2. 2.21² =
  3. 3.79² =
  4. 4.41² =
  5. 5.49² =
  6. 6.59² =
  7. 7.51² =
  8. 8.79² =
  9. 9.81² =
  10. 10.59² =
  11. 11.39² =
  12. 12.21² =
  13. 13.59² =
  14. 14.81² =
  15. 15.49² =
  16. 16.79² =
  17. 17.21² =
  18. 18.69² =
  19. 19.91² =
  20. 20.21² =
  21. 21.91² =
  22. 22.81² =
  23. 23.39² =
  24. 24.91² =
  25. 25.39² =
  26. 26.71² =
  27. 27.29² =
  28. 28.49² =
  29. 29.39² =
  30. 30.29² =
  31. 31.71² =
  32. 32.89² =
  33. 33.39² =
  34. 34.61² =
  35. 35.69² =
  36. 36.31² =
  37. 37.19² =
  38. 38.81² =
  39. 39.69² =
  40. 40.89² =

Answer key

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

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