2．用递等式计算．
0 159845 159853 159859 159863 159869 159871 159875 159881 159883 159889 159895 159899 159901 159905 159911 159913 159919 159923 159925 159929 159931 159935 159937 159939 159940 159941 159943 159944 159945 159947 159949 159953 159955 159959 159961 159965 159971 159973 159979 159983 159985 159989 159995 160001 160003 160009 160013 160015 160021 160025 160031 160039 199269
| 10÷$\frac{4}{25}$÷$\frac{5}{12}$ | $\frac{7}{11}$÷$\frac{7}{8}$×$\frac{11}{12}$ | $\frac{9}{10}$×15÷$\frac{3}{5}$ |
| 1-$\frac{3}{8}$÷$\frac{7}{5}$ | 19÷$\frac{11}{5}$+3×$\frac{5}{11}$ | $\frac{1}{2}$÷（2×$\frac{5}{6}$） |