*so sánh:
a)\(\frac{-12}{17}\)và \(\frac{13}{-18}\)
b) \(\frac{-17}{26}\)và\(\frac{-16}{27}\)
* Tính hợp lí
\(\frac{2}{39}+\frac{1}{15}+\frac{2}{153}\)/ \(\frac{1}{34}+\frac{3}{20}+\frac{3}{26}\): \(1+\frac{2}{71}\frac{5}{121}\)/ \(\frac{65}{121}-\frac{26}{71}-13\)