1)20/11+20/13=2+9/11+7/13=2+333/407+21/39;
50/37+50/39=2+13/37+11/39=2+143/407+11/39.
比较结果可知:20/11+20/13>50/37+50/39.
2)设括号内为A,即5/9
1)20/11+20/13=2+9/11+7/13=2+333/407+21/39;
50/37+50/39=2+13/37+11/39=2+143/407+11/39.
比较结果可知:20/11+20/13>50/37+50/39.
2)设括号内为A,即5/9