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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 684 · 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. 1.21² =
  2. 2.61² =
  3. 3.89² =
  4. 4.31² =
  5. 5.19² =
  6. 6.31² =
  7. 7.59² =
  8. 8.79² =
  9. 9.79² =
  10. 10.21² =
  11. 11.39² =
  12. 12.89² =
  13. 13.79² =
  14. 14.71² =
  15. 15.31² =
  16. 16.51² =
  17. 17.59² =
  18. 18.61² =
  19. 19.59² =
  20. 20.81² =
  21. 21.21² =
  22. 22.51² =
  23. 23.69² =
  24. 24.61² =
  25. 25.69² =
  26. 26.79² =
  27. 27.51² =
  28. 28.61² =
  29. 29.61² =
  30. 30.81² =
  31. 31.39² =
  32. 32.41² =
  33. 33.71² =
  34. 34.49² =
  35. 35.29² =
  36. 36.39² =
  37. 37.39² =
  38. 38.59² =
  39. 39.59² =
  40. 40.51² =

Answer key

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

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