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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 890 · 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. 1.61² =
  2. 2.29² =
  3. 3.49² =
  4. 4.39² =
  5. 5.89² =
  6. 6.51² =
  7. 7.51² =
  8. 8.29² =
  9. 9.81² =
  10. 10.89² =
  11. 11.61² =
  12. 12.29² =
  13. 13.71² =
  14. 14.49² =
  15. 15.61² =
  16. 16.19² =
  17. 17.41² =
  18. 18.91² =
  19. 19.79² =
  20. 20.69² =
  21. 21.91² =
  22. 22.91² =
  23. 23.89² =
  24. 24.79² =
  25. 25.29² =
  26. 26.41² =
  27. 27.19² =
  28. 28.29² =
  29. 29.29² =
  30. 30.19² =
  31. 31.81² =
  32. 32.21² =
  33. 33.31² =
  34. 34.61² =
  35. 35.29² =
  36. 36.19² =
  37. 37.29² =
  38. 38.89² =
  39. 39.21² =
  40. 40.49² =

Answer key

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

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