[2.25+（3

3

5

÷1.8-1.21×

5

11

）]÷40%，
=[2.25+（

18

5

÷

9

5

-0.55）]÷40%，
=[2.25+（

18

5

×

5

9

-0.55）]÷40%，
=[2.25+（2-0.55）]÷40%，
=[2.25+（2-0.55）]÷40%，
=3.7÷0.4，
=9.25．