2．口算．
0 158809 158817 158823 158827 158833 158835 158839 158845 158847 158853 158859 158863 158865 158869 158875 158877 158883 158887 158889 158893 158895 158899 158901 158903 158904 158905 158907 158908 158909 158911 158913 158917 158919 158923 158925 158929 158935 158937 158943 158947 158949 158953 158959 158965 158967 158973 158977 158979 158985 158989 158995 159003 199269
| 32÷0.1 | $\frac{1}{3}$-$\frac{1}{5}$ | 6+$\frac{5}{6}$ | 2.1-2.09 |
| $\frac{3}{16}$×$\frac{4}{9}$ | 20×5.5 | 1÷$\frac{2}{3}$ | 548+199 |
| $\frac{2}{3}$÷$\frac{3}{2}$ | 1.25×0.16×8 | $\frac{5}{4}$×8+8×$\frac{1}{4}$ | 0.1÷0.01×0.001 |