一、口算。
拍照批改
$3.8+6.2=$ $0.02÷80\% =$ $5-0.25+0.75=$
$\frac {3}{5}+\frac {4}{5}=$ $9.1÷70\% =$ $2÷\frac {2}{5}-\frac {2}{5}=$
$\frac {4}{5}×\frac {3}{2}=$ $8.1+0.25=$ $\frac {1}{6}×13-\frac {1}{6}=$
$70\% +\frac {2}{5}=$ $\frac {7}{8}÷\frac {14}{17}=$ $32+4.9-0.9=$
$\frac {3}{4}-\frac {2}{5}=$ $1÷\frac {3}{8}=$ $\frac {9}{7}-\frac {1}{6}-\frac {5}{6}=$
$3.57÷7=$ $32×12.5\% =$ $13×(2+\frac {7}{13})=$
$3.7×0.1\% =$ $1.1-25\% =$ $\frac {2}{7}×7÷\frac {2}{7}×7=$

10 0.025 5.5 $\frac{7}{5}$ 13 $4\frac{3}{5}$ $\frac{6}{5}$ 8.35 2 1.1 $\frac{17}{16}$ 36 $\frac{7}{20}$ $\frac{8}{3}$ $\frac{2}{7}$ 0.51 4 33 0.0037 0.85 49

$3.8+6.2=10$
$0.02÷80\% =0.025$
$5-0.25+0.75=5.5$
$\frac {3}{5}+\frac {4}{5}=\frac {7}{5}$
$9.1÷70\% =13$
$2÷\frac {2}{5}-\frac {2}{5}=4\frac {3}{5}$
$\frac {4}{5}×\frac {3}{2}=\frac {6}{5}$
$8.1+0.25=8.35$
$\frac {1}{6}×13-\frac {1}{6}=2$
$70\% +\frac {2}{5}=1.1$
$\frac {7}{8}÷\frac {14}{17}=\frac {17}{16}$
$32+4.9-0.9=36$
$\frac {3}{4}-\frac {2}{5}=\frac {7}{20}$
$1÷\frac {3}{8}=\frac {8}{3}$
$\frac {9}{7}-\frac {1}{6}-\frac {5}{6}=\frac {2}{7}$
$3.57÷7=0.51$
$32×12.5\% =4$
$13×(2+\frac {7}{13})=33$
$3.7×0.1\% =0.0037$
$1.1-25\% =0.85$
$\frac {2}{7}×7÷\frac {2}{7}×7=49$

二、计算下面各题。
$35×(1-\frac {3}{7})÷\frac {5}{12}$ $1-(\frac {7}{12}-50\% )÷12.5\% $ $\frac {4}{5}×\frac {8}{7}+\frac {6}{7}÷125\% $
$32×\frac {33}{34}÷\frac {32}{33}$ $(\frac {5}{9}-\frac {1}{18})×(\frac {3}{4}+\frac {1}{6})$ $[\frac {4}{5}-(\frac {3}{5}-\frac {1}{3})]÷\frac {4}{15}$

48 $\frac{1}{3}$ $\frac{8}{5}$ $32\frac{1}{34}$ $\frac{11}{24}$ 2

1. $35×(1-\frac {3}{7})÷\frac {5}{12}$
= $35×\frac{4}{7}÷\frac{5}{12}$
= $20×\frac{12}{5}$
= 48
2. $1-(\frac {7}{12}-50\% )÷12.5\%$
= $1-(\frac{7}{12}-\frac{6}{12})÷\frac{1}{8}$
= $1-\frac{1}{12}×8$
= $1-\frac{2}{3}$
= $\frac{1}{3}$
3. $\frac {4}{5}×\frac {8}{7}+\frac {6}{7}÷125\%$
= $\frac{4}{5}×\frac{8}{7}+\frac{6}{7}×\frac{4}{5}$
= $\frac{4}{5}×(\frac{8}{7}+\frac{6}{7})$
= $\frac{4}{5}×2$
= $\frac{8}{5}$
4. $32×\frac {33}{34}÷\frac {32}{33}$
= $32×\frac{33}{34}×\frac{33}{32}$
= $\frac{33×33}{34}$
= $\frac{1089}{34}$
= $32\frac{1}{34}$
5. $(\frac {5}{9}-\frac {1}{18})×(\frac {3}{4}+\frac {1}{6})$
= $(\frac{10}{18}-\frac{1}{18})×(\frac{9}{12}+\frac{2}{12})$
= $\frac{9}{18}×\frac{11}{12}$
= $\frac{1}{2}×\frac{11}{12}$
= $\frac{11}{24}$
6. $[\frac {4}{5}-(\frac {3}{5}-\frac {1}{3})]÷\frac {4}{15}$
= $[\frac{4}{5}-\frac{3}{5}+\frac{1}{3}]×\frac{15}{4}$
= $[\frac{1}{5}+\frac{1}{3}]×\frac{15}{4}$
= $\frac{8}{15}×\frac{15}{4}$
= 2