4.2/9+3.4/9-6.5/-2.3/11+2.5/.1/8-5.7/8)+2.5/8

4.2/9+3.4/9-6.5/9=1.1/9   
1)4.2/9+3.4/9=7.6/9
2)7.6/9-6.5/9=1.1/9

3-2.3/11+2.5/11= -1.8/11
1)2.3/11+2.5/11=4.8/11
2)3-4.8/11= -1.8/11

(8.1/8-5.7/8)+2.5/8=4.7/8
1)8.1/8-5.7/8=2.1/4
2)2.1/4+2.5/8=4.7/8