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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 223 · 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. 1.91² =
  2. 2.81² =
  3. 3.69² =
  4. 4.49² =
  5. 5.69² =
  6. 6.49² =
  7. 7.29² =
  8. 8.39² =
  9. 9.89² =
  10. 10.31² =
  11. 11.19² =
  12. 12.39² =
  13. 13.59² =
  14. 14.79² =
  15. 15.91² =
  16. 16.59² =
  17. 17.39² =
  18. 18.21² =
  19. 19.29² =
  20. 20.89² =
  21. 21.51² =
  22. 22.51² =
  23. 23.51² =
  24. 24.61² =
  25. 25.59² =
  26. 26.51² =
  27. 27.31² =
  28. 28.71² =
  29. 29.59² =
  30. 30.51² =
  31. 31.69² =
  32. 32.41² =
  33. 33.79² =
  34. 34.89² =
  35. 35.91² =
  36. 36.79² =
  37. 37.19² =
  38. 38.49² =
  39. 39.31² =
  40. 40.21² =

Answer key

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

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