$\frac{3}{5}$ ＋ $\frac{3}{7}$ ＋ $\frac{2}{5}$ = ( )

Dear friend,
       I am an American (美国的 ) girl. My name is Alice Green. I am a middle school student. I am fifteen. I have two brothers. They are middle school students, too. We go to school from Monday to Friday. We don't have any classes on Saturdays and Sundays. My father and mother are teachers. They always say China is great. I like reading. I am reading a Chinese book. I think it's very interesting. My brothers and I like playing football and basketball. What sports do you like?
     Let's be good pen pals (笔友), OK? Please write to me soon.
Yours,
Alice Green

如图是初中化学中常见仪器装置，回答下列问题：