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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 570 · 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. 2.39² =
  3. 3.21² =
  4. 4.71² =
  5. 5.59² =
  6. 6.59² =
  7. 7.19² =
  8. 8.69² =
  9. 9.89² =
  10. 10.21² =
  11. 11.79² =
  12. 12.59² =
  13. 13.59² =
  14. 14.31² =
  15. 15.91² =
  16. 16.69² =
  17. 17.71² =
  18. 18.29² =
  19. 19.49² =
  20. 20.39² =
  21. 21.39² =
  22. 22.89² =
  23. 23.51² =
  24. 24.81² =
  25. 25.19² =
  26. 26.91² =
  27. 27.21² =
  28. 28.59² =
  29. 29.39² =
  30. 30.41² =
  31. 31.41² =
  32. 32.31² =
  33. 33.91² =
  34. 34.19² =
  35. 35.69² =
  36. 36.61² =
  37. 37.31² =
  38. 38.59² =
  39. 39.21² =
  40. 40.89² =

Answer key

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

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