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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 831 · 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. 1.41² =
  2. 2.41² =
  3. 3.19² =
  4. 4.49² =
  5. 5.51² =
  6. 6.69² =
  7. 7.49² =
  8. 8.39² =
  9. 9.59² =
  10. 10.71² =
  11. 11.39² =
  12. 12.79² =
  13. 13.81² =
  14. 14.61² =
  15. 15.29² =
  16. 16.39² =
  17. 17.39² =
  18. 18.21² =
  19. 19.49² =
  20. 20.79² =
  21. 21.71² =
  22. 22.81² =
  23. 23.71² =
  24. 24.29² =
  25. 25.61² =
  26. 26.89² =
  27. 27.51² =
  28. 28.89² =
  29. 29.39² =
  30. 30.39² =
  31. 31.89² =
  32. 32.79² =
  33. 33.69² =
  34. 34.81² =
  35. 35.71² =
  36. 36.29² =
  37. 37.39² =
  38. 38.19² =
  39. 39.61² =
  40. 40.29² =

Answer key

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

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