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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 668 · 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. 2.39² =
  3. 3.19² =
  4. 4.39² =
  5. 5.89² =
  6. 6.81² =
  7. 7.19² =
  8. 8.51² =
  9. 9.29² =
  10. 10.51² =
  11. 11.21² =
  12. 12.61² =
  13. 13.41² =
  14. 14.89² =
  15. 15.89² =
  16. 16.39² =
  17. 17.79² =
  18. 18.81² =
  19. 19.49² =
  20. 20.19² =
  21. 21.61² =
  22. 22.19² =
  23. 23.89² =
  24. 24.21² =
  25. 25.81² =
  26. 26.29² =
  27. 27.69² =
  28. 28.81² =
  29. 29.49² =
  30. 30.71² =
  31. 31.61² =
  32. 32.69² =
  33. 33.59² =
  34. 34.79² =
  35. 35.79² =
  36. 36.29² =
  37. 37.79² =
  38. 38.71² =
  39. 39.71² =
  40. 40.89² =

Answer key

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

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