(20 16/25+13 9/25)-(23 4/14+7 13/14)=34-31 3/14=2 11/14
1) 20 16/25+13 9/25= 33 25/25=34;
2) 23 4/14+7 13/14= 30 17/14=31 3/14;
3) 34-31 3/14=33 14/14-31 3/14=2 11/14