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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 205 · 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. 1.29² =
  2. 2.81² =
  3. 3.49² =
  4. 4.71² =
  5. 5.71² =
  6. 6.61² =
  7. 7.79² =
  8. 8.21² =
  9. 9.39² =
  10. 10.59² =
  11. 11.81² =
  12. 12.81² =
  13. 13.69² =
  14. 14.31² =
  15. 15.61² =
  16. 16.19² =
  17. 17.19² =
  18. 18.91² =
  19. 19.61² =
  20. 20.41² =
  21. 21.21² =
  22. 22.59² =
  23. 23.39² =
  24. 24.61² =
  25. 25.79² =
  26. 26.61² =
  27. 27.61² =
  28. 28.91² =
  29. 29.59² =
  30. 30.59² =
  31. 31.21² =
  32. 32.61² =
  33. 33.79² =
  34. 34.39² =
  35. 35.59² =
  36. 36.51² =
  37. 37.71² =
  38. 38.89² =
  39. 39.59² =
  40. 40.19² =

Answer key

  1. 841
  2. 6561
  3. 2401
  4. 5041
  5. 5041
  6. 3721
  7. 6241
  8. 441
  9. 1521
  10. 3481
  11. 6561
  12. 6561
  13. 4761
  14. 961
  15. 3721
  16. 361
  17. 361
  18. 8281
  19. 3721
  20. 1681
  21. 441
  22. 3481
  23. 1521
  24. 3721
  25. 6241
  26. 3721
  27. 3721
  28. 8281
  29. 3481
  30. 3481
  31. 441
  32. 3721
  33. 6241
  34. 1521
  35. 3481
  36. 2601
  37. 5041
  38. 7921
  39. 3481
  40. 361

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