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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 991 · 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. 1.31² =
  2. 2.89² =
  3. 3.91² =
  4. 4.69² =
  5. 5.69² =
  6. 6.81² =
  7. 7.21² =
  8. 8.79² =
  9. 9.79² =
  10. 10.71² =
  11. 11.81² =
  12. 12.39² =
  13. 13.69² =
  14. 14.69² =
  15. 15.29² =
  16. 16.89² =
  17. 17.19² =
  18. 18.89² =
  19. 19.69² =
  20. 20.31² =
  21. 21.49² =
  22. 22.49² =
  23. 23.49² =
  24. 24.89² =
  25. 25.29² =
  26. 26.29² =
  27. 27.79² =
  28. 28.19² =
  29. 29.81² =
  30. 30.59² =
  31. 31.81² =
  32. 32.31² =
  33. 33.69² =
  34. 34.49² =
  35. 35.51² =
  36. 36.41² =
  37. 37.71² =
  38. 38.41² =
  39. 39.29² =
  40. 40.69² =

Answer key

  1. 961
  2. 7921
  3. 8281
  4. 4761
  5. 4761
  6. 6561
  7. 441
  8. 6241
  9. 6241
  10. 5041
  11. 6561
  12. 1521
  13. 4761
  14. 4761
  15. 841
  16. 7921
  17. 361
  18. 7921
  19. 4761
  20. 961
  21. 2401
  22. 2401
  23. 2401
  24. 7921
  25. 841
  26. 841
  27. 6241
  28. 361
  29. 6561
  30. 3481
  31. 6561
  32. 961
  33. 4761
  34. 2401
  35. 2601
  36. 1681
  37. 5041
  38. 1681
  39. 841
  40. 4761

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