第21页

信息发布者:

$\begin{aligned}&\frac{7}{9}×\frac{2}{3}+\frac{7}{9}÷3\\=&\frac{7}{9}×\frac{2}{3}+\frac{7}{9}×\frac{1}{3}\\=&\frac{7}{9}×(\frac{2}{3}+\frac{1}{3})\\=&\frac{7}{9}×1\\=&\frac{7}{9}\end{aligned}$

$\begin{aligned}&4 - \frac{2}{5}÷\frac{16}{25}-\frac{3}{8}\\=&4 - \frac{2}{5}×\frac{25}{16}-\frac{3}{8}\\=&4 - \frac{5}{8}-\frac{3}{8}\\=&4 - (\frac{5}{8}+\frac{3}{8})\\=&4 - 1\\=&3\end{aligned}$

$\begin{aligned}&60×(\frac{1}{3}+\frac{1}{4}+\frac{1}{5})\\=&60×\frac{1}{3}+60×\frac{1}{4}+60×\frac{1}{5}\\=&20 + 15 + 12\\=&47\end{aligned}$

$\begin{aligned}&1.25×9÷\frac{1}{8}\\=&1.25×9×8\\=&(1.25×8)×9\\=&10×9\\=&90\end{aligned}$
解:
$\begin{aligned}x + 30\%x&=5.2\\1.3x&=5.2\\x&=5.2÷1.3\\x&=4\end{aligned}$
解:
$\begin{aligned}\frac{4}{5}x+\frac{1}{5}&=5\\\frac{4}{5}x&=5 - \frac{1}{5}\\\frac{4}{5}x&=\frac{24}{5}\\x&=\frac{24}{5}÷\frac{4}{5}\\x&=6\end{aligned}$

​$3÷\frac {3}{4}=4($​段​$)$​

小筐​$:(445−8×15)÷(8+5)=25($​千克​$) $​
大筐​$:25+15 =40($​千克​$)$​
答:大筐装​$40$​千克,小筐装​$25$​千克。