2.( 1)4, 25, 0.8(2) 16/9, 28

do it yourself

4. Thirty-one twentieth, seven twelfth, four and twelve sevenths.

5.X= 2 1/8，X= 77/ 160。

6. Twenty-five out of seventy-eight, seventy-seven out of twelve, three out of sixty and seventeen out of two hundred and sixteen.

I called myself and stopped.