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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 191 · 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. 1.91² =
  2. 2.21² =
  3. 3.39² =
  4. 4.69² =
  5. 5.89² =
  6. 6.69² =
  7. 7.19² =
  8. 8.39² =
  9. 9.79² =
  10. 10.51² =
  11. 11.31² =
  12. 12.21² =
  13. 13.31² =
  14. 14.21² =
  15. 15.31² =
  16. 16.91² =
  17. 17.69² =
  18. 18.59² =
  19. 19.61² =
  20. 20.59² =
  21. 21.61² =
  22. 22.89² =
  23. 23.39² =
  24. 24.71² =
  25. 25.91² =
  26. 26.61² =
  27. 27.69² =
  28. 28.19² =
  29. 29.81² =
  30. 30.39² =
  31. 31.31² =
  32. 32.61² =
  33. 33.21² =
  34. 34.71² =
  35. 35.89² =
  36. 36.19² =
  37. 37.81² =
  38. 38.19² =
  39. 39.29² =
  40. 40.39² =

Answer key

  1. 8281
  2. 441
  3. 1521
  4. 4761
  5. 7921
  6. 4761
  7. 361
  8. 1521
  9. 6241
  10. 2601
  11. 961
  12. 441
  13. 961
  14. 441
  15. 961
  16. 8281
  17. 4761
  18. 3481
  19. 3721
  20. 3481
  21. 3721
  22. 7921
  23. 1521
  24. 5041
  25. 8281
  26. 3721
  27. 4761
  28. 361
  29. 6561
  30. 1521
  31. 961
  32. 3721
  33. 441
  34. 5041
  35. 7921
  36. 361
  37. 6561
  38. 361
  39. 841
  40. 1521

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