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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 309 · 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. 1.69² =
  2. 2.89² =
  3. 3.89² =
  4. 4.21² =
  5. 5.19² =
  6. 6.41² =
  7. 7.61² =
  8. 8.39² =
  9. 9.31² =
  10. 10.79² =
  11. 11.49² =
  12. 12.21² =
  13. 13.59² =
  14. 14.71² =
  15. 15.79² =
  16. 16.89² =
  17. 17.59² =
  18. 18.59² =
  19. 19.81² =
  20. 20.19² =
  21. 21.19² =
  22. 22.49² =
  23. 23.71² =
  24. 24.81² =
  25. 25.69² =
  26. 26.61² =
  27. 27.49² =
  28. 28.39² =
  29. 29.69² =
  30. 30.39² =
  31. 31.91² =
  32. 32.21² =
  33. 33.79² =
  34. 34.21² =
  35. 35.81² =
  36. 36.49² =
  37. 37.21² =
  38. 38.41² =
  39. 39.29² =
  40. 40.81² =

Answer key

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

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