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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 858 · 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. 1.89² =
  2. 2.39² =
  3. 3.49² =
  4. 4.69² =
  5. 5.51² =
  6. 6.51² =
  7. 7.51² =
  8. 8.89² =
  9. 9.89² =
  10. 10.49² =
  11. 11.89² =
  12. 12.79² =
  13. 13.29² =
  14. 14.29² =
  15. 15.89² =
  16. 16.39² =
  17. 17.51² =
  18. 18.51² =
  19. 19.39² =
  20. 20.79² =
  21. 21.69² =
  22. 22.49² =
  23. 23.69² =
  24. 24.79² =
  25. 25.29² =
  26. 26.19² =
  27. 27.21² =
  28. 28.69² =
  29. 29.49² =
  30. 30.71² =
  31. 31.91² =
  32. 32.41² =
  33. 33.19² =
  34. 34.29² =
  35. 35.51² =
  36. 36.79² =
  37. 37.79² =
  38. 38.69² =
  39. 39.79² =
  40. 40.89² =

Answer key

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

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