一、口算。
$\frac{8}{10}-\frac{5}{10}=$ $\frac{3}{4}+\frac{11}{4}=$ $\frac{11}{6}-\frac{7}{6}=$
$\frac{2}{7}+\frac{11}{7}=$ $\frac{13}{15}-\frac{1}{15}=$ $\frac{11}{8}+\frac{4}{8}=$
$\frac{9}{12}-\frac{4}{12}=$ $\frac{5}{13}+\frac{6}{13}=$ $\frac{18}{24}-\frac{7}{24}=$
$0.65×4=$ $21.5+9.5=$ $8.2÷0.01=$
$6.3+2.75=$ $8.1÷30=$ $4.28-3.08=$
$5-4.26=$ $0.7×0.8=$ $2.7÷0.03=$
$2.42+0.58=$ $5.4÷0.09=$ $3.45-1.63=$
$12.5-7.6=$ $4×0.125=$ $0.84÷0.06=$
$0.46÷2.3=$ $2.82-0.6=$ $5.82+3.28=$
$4.1+0.47=$ $0.35×0.2=$ $3÷0.05=$

$\frac{3}{10}$ $\frac{7}{2}$ $\frac{2}{3}$
$\frac{13}{7}$ $\frac{4}{5}$ $\frac{15}{8}$
$\frac{5}{12}$ $\frac{11}{13}$ $\frac{11}{24}$
$2.6$ $31$ $820$
$9.05$ $0.27$ $1.2$
$0.74$ $0.56$ $90$
$3$ $60$ $1.82$
$4.9$ $0.5$ $14$
$0.2$ $2.22$ $9.1$
$4.57$ $0.07$ $60$

二、把没有约成最简分数的约成最简分数。
$\frac{27}{36}=\frac{9}{12}$ $\frac{24}{36}=\frac{6}{9}$ $\frac{48}{60}=\frac{8}{10}$ $\frac{32}{60}=\frac{16}{30}$

$\frac{27}{36}=\frac{3}{4}$ $\frac{24}{36}=\frac{2}{3}$
$\frac{48}{60}=\frac{4}{5}$ $\frac{32}{60}=\frac{8}{15}$