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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 847 · 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. 1.79² =
  2. 2.69² =
  3. 3.91² =
  4. 4.29² =
  5. 5.91² =
  6. 6.49² =
  7. 7.89² =
  8. 8.69² =
  9. 9.89² =
  10. 10.69² =
  11. 11.21² =
  12. 12.69² =
  13. 13.89² =
  14. 14.41² =
  15. 15.61² =
  16. 16.19² =
  17. 17.89² =
  18. 18.29² =
  19. 19.41² =
  20. 20.91² =
  21. 21.81² =
  22. 22.39² =
  23. 23.29² =
  24. 24.71² =
  25. 25.79² =
  26. 26.81² =
  27. 27.41² =
  28. 28.29² =
  29. 29.49² =
  30. 30.29² =
  31. 31.31² =
  32. 32.59² =
  33. 33.61² =
  34. 34.61² =
  35. 35.49² =
  36. 36.29² =
  37. 37.29² =
  38. 38.81² =
  39. 39.41² =
  40. 40.21² =

Answer key

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

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