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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 160 · 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. 1.81² =
  2. 2.41² =
  3. 3.51² =
  4. 4.89² =
  5. 5.21² =
  6. 6.49² =
  7. 7.41² =
  8. 8.79² =
  9. 9.71² =
  10. 10.21² =
  11. 11.39² =
  12. 12.89² =
  13. 13.29² =
  14. 14.41² =
  15. 15.21² =
  16. 16.59² =
  17. 17.89² =
  18. 18.69² =
  19. 19.61² =
  20. 20.81² =
  21. 21.21² =
  22. 22.29² =
  23. 23.51² =
  24. 24.91² =
  25. 25.91² =
  26. 26.79² =
  27. 27.19² =
  28. 28.39² =
  29. 29.91² =
  30. 30.51² =
  31. 31.51² =
  32. 32.21² =
  33. 33.81² =
  34. 34.61² =
  35. 35.29² =
  36. 36.29² =
  37. 37.71² =
  38. 38.61² =
  39. 39.59² =
  40. 40.71² =

Answer key

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

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