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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 947 · 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. 2.19² =
  3. 3.61² =
  4. 4.81² =
  5. 5.89² =
  6. 6.49² =
  7. 7.61² =
  8. 8.91² =
  9. 9.59² =
  10. 10.81² =
  11. 11.91² =
  12. 12.19² =
  13. 13.39² =
  14. 14.49² =
  15. 15.59² =
  16. 16.19² =
  17. 17.31² =
  18. 18.29² =
  19. 19.21² =
  20. 20.29² =
  21. 21.79² =
  22. 22.79² =
  23. 23.91² =
  24. 24.69² =
  25. 25.61² =
  26. 26.81² =
  27. 27.59² =
  28. 28.59² =
  29. 29.81² =
  30. 30.49² =
  31. 31.31² =
  32. 32.39² =
  33. 33.39² =
  34. 34.59² =
  35. 35.61² =
  36. 36.61² =
  37. 37.69² =
  38. 38.41² =
  39. 39.29² =
  40. 40.89² =

Answer key

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

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