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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 278 · 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. 1.71² =
  2. 2.39² =
  3. 3.41² =
  4. 4.69² =
  5. 5.51² =
  6. 6.21² =
  7. 7.19² =
  8. 8.19² =
  9. 9.19² =
  10. 10.71² =
  11. 11.39² =
  12. 12.39² =
  13. 13.71² =
  14. 14.79² =
  15. 15.69² =
  16. 16.79² =
  17. 17.79² =
  18. 18.19² =
  19. 19.51² =
  20. 20.39² =
  21. 21.29² =
  22. 22.39² =
  23. 23.91² =
  24. 24.69² =
  25. 25.59² =
  26. 26.19² =
  27. 27.31² =
  28. 28.71² =
  29. 29.19² =
  30. 30.71² =
  31. 31.59² =
  32. 32.39² =
  33. 33.61² =
  34. 34.91² =
  35. 35.79² =
  36. 36.81² =
  37. 37.21² =
  38. 38.21² =
  39. 39.51² =
  40. 40.39² =

Answer key

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

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