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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 420 · 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. 2.29² =
  3. 3.21² =
  4. 4.79² =
  5. 5.71² =
  6. 6.19² =
  7. 7.31² =
  8. 8.41² =
  9. 9.79² =
  10. 10.41² =
  11. 11.41² =
  12. 12.49² =
  13. 13.81² =
  14. 14.19² =
  15. 15.39² =
  16. 16.31² =
  17. 17.71² =
  18. 18.39² =
  19. 19.91² =
  20. 20.39² =
  21. 21.19² =
  22. 22.29² =
  23. 23.71² =
  24. 24.51² =
  25. 25.89² =
  26. 26.19² =
  27. 27.31² =
  28. 28.89² =
  29. 29.81² =
  30. 30.79² =
  31. 31.31² =
  32. 32.59² =
  33. 33.49² =
  34. 34.39² =
  35. 35.61² =
  36. 36.49² =
  37. 37.39² =
  38. 38.21² =
  39. 39.49² =
  40. 40.61² =

Answer key

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

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