1. 计算下面各题。
$789 + 960 ÷ 15 × 13$ $16 × 45 - 735 ÷ 21$
$666 ÷ (901 - 32 × 27)$ $909 × [(118 + 602) ÷ 80]$
$(\frac{1}{2} + \frac{1}{6}) × (\frac{1}{3} - \frac{1}{4})$ $\frac{3}{5} ÷ [\frac{3}{8} × (\frac{4}{15} + \frac{2}{5})]$
$789 + 960 ÷ 15 × 13$ $16 × 45 - 735 ÷ 21$
$666 ÷ (901 - 32 × 27)$ $909 × [(118 + 602) ÷ 80]$
$(\frac{1}{2} + \frac{1}{6}) × (\frac{1}{3} - \frac{1}{4})$ $\frac{3}{5} ÷ [\frac{3}{8} × (\frac{4}{15} + \frac{2}{5})]$
答案：=789+64×13
=789+832
=1621
=720-735÷21
=720-35
=685
=666÷(901-864)
=666÷37
=18
=909×[720÷80]
=909×9
=8181
$ =\frac {2}{3}×\frac {1}{12}$
$ =\frac {1}{18}$
$ =\frac {3}{5}\div [\frac {3}{8}×\frac {2}{3}]$
$ =\frac {3}{5}\div \frac {1}{4}$
$ =\frac {12}{5}$
=789+832
=1621
=720-735÷21
=720-35
=685
=666÷(901-864)
=666÷37
=18
=909×[720÷80]
=909×9
=8181
$ =\frac {2}{3}×\frac {1}{12}$
$ =\frac {1}{18}$
$ =\frac {3}{5}\div [\frac {3}{8}×\frac {2}{3}]$
$ =\frac {3}{5}\div \frac {1}{4}$
$ =\frac {12}{5}$
2. 用简便方法计算。
$48 + 169 + 52$ $25 × 73 × 0.4$ $43 × 102$
$\frac{4}{9} + \frac{3}{17} + \frac{5}{9} + \frac{4}{17}$ $\frac{7}{18} × \frac{5}{4} + \frac{11}{18} ÷ \frac{4}{5}$
$48 + 169 + 52$ $25 × 73 × 0.4$ $43 × 102$
$\frac{4}{9} + \frac{3}{17} + \frac{5}{9} + \frac{4}{17}$ $\frac{7}{18} × \frac{5}{4} + \frac{11}{18} ÷ \frac{4}{5}$
答案：=48+52+169
=100+169
=269
=25×0.4×73
=10×73
=730
=43×(100+2)
=43×100+43×2
=4300+86
=4386
$ =(\frac {4}{9}+\frac {5}{9})+(\frac {3}{17}+\frac {4}{17})$
$ =1+\frac {7}{17}$
$ =1\frac {7}{17}$
$=(\frac {7}{18}+\frac {11}{18})×\frac {5}{4}$
$ =1×\frac {5}{4}$
$ =\frac {5}{4}$
=100+169
=269
=25×0.4×73
=10×73
=730
=43×(100+2)
=43×100+43×2
=4300+86
=4386
$ =(\frac {4}{9}+\frac {5}{9})+(\frac {3}{17}+\frac {4}{17})$
$ =1+\frac {7}{17}$
$ =1\frac {7}{17}$
$=(\frac {7}{18}+\frac {11}{18})×\frac {5}{4}$
$ =1×\frac {5}{4}$
$ =\frac {5}{4}$