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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 487 · 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. 1.39² =
  2. 2.61² =
  3. 3.71² =
  4. 4.79² =
  5. 5.61² =
  6. 6.71² =
  7. 7.81² =
  8. 8.69² =
  9. 9.59² =
  10. 10.19² =
  11. 11.39² =
  12. 12.49² =
  13. 13.21² =
  14. 14.69² =
  15. 15.39² =
  16. 16.59² =
  17. 17.29² =
  18. 18.61² =
  19. 19.89² =
  20. 20.21² =
  21. 21.61² =
  22. 22.41² =
  23. 23.79² =
  24. 24.39² =
  25. 25.79² =
  26. 26.61² =
  27. 27.91² =
  28. 28.61² =
  29. 29.19² =
  30. 30.39² =
  31. 31.31² =
  32. 32.89² =
  33. 33.91² =
  34. 34.81² =
  35. 35.29² =
  36. 36.59² =
  37. 37.49² =
  38. 38.29² =
  39. 39.19² =
  40. 40.39² =

Answer key

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

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