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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 989 · 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. 1.49² =
  2. 2.81² =
  3. 3.69² =
  4. 4.21² =
  5. 5.71² =
  6. 6.71² =
  7. 7.89² =
  8. 8.91² =
  9. 9.41² =
  10. 10.79² =
  11. 11.19² =
  12. 12.29² =
  13. 13.39² =
  14. 14.21² =
  15. 15.91² =
  16. 16.71² =
  17. 17.49² =
  18. 18.39² =
  19. 19.39² =
  20. 20.79² =
  21. 21.61² =
  22. 22.89² =
  23. 23.21² =
  24. 24.61² =
  25. 25.19² =
  26. 26.51² =
  27. 27.81² =
  28. 28.39² =
  29. 29.69² =
  30. 30.61² =
  31. 31.81² =
  32. 32.39² =
  33. 33.51² =
  34. 34.81² =
  35. 35.21² =
  36. 36.79² =
  37. 37.89² =
  38. 38.41² =
  39. 39.81² =
  40. 40.91² =

Answer key

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

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