1.脱式计算。
$1-\frac{3}{7}+\frac{5}{14}$
$\frac{7}{8}-\frac{3}{8}+\frac{1}{4}$
$1-(\frac{1}{2}-\frac{1}{4})$
$\frac{5}{7}+\frac{1}{7}+\frac{2}{7}$
$\frac{2}{5}+\frac{1}{3}+\frac{3}{5}$
$\frac{8}{15}-(\frac{8}{15}-\frac{7}{18})$
$\frac{6}{7}+\frac{8}{11}+\frac{3}{11}$
$\frac{2}{3}-(\frac{2}{3}-\frac{1}{2})$
$\frac{3}{4}-(\frac{1}{2}+\frac{1}{4})$

$1-\frac{3}{7}+\frac{5}{14}$
$=\frac{14}{14}-\frac{6}{14}+\frac{5}{14}$
$=\frac{8}{14}+\frac{5}{14}$
$=\frac{13}{14}$
$\frac{7}{8}-\frac{3}{8}+\frac{1}{4}$
$=\frac{4}{8}+\frac{1}{4}$
$=\frac{1}{2}+\frac{1}{4}$
$=\frac{2}{4}+\frac{1}{4}$
$=\frac{3}{4}$
$1-(\frac{1}{2}-\frac{1}{4})$
$=1-(\frac{2}{4}-\frac{1}{4})$
$=1-\frac{1}{4}$
$=\frac{3}{4}$
$\frac{5}{7}+\frac{1}{7}+\frac{2}{7}$
$=\frac{6}{7}+\frac{2}{7}$
$=\frac{8}{7}$
$\frac{2}{5}+\frac{1}{3}+\frac{3}{5}$
$=\frac{2}{5}+\frac{3}{5}+\frac{1}{3}$
$=1+\frac{1}{3}$
$=\frac{4}{3}$
$\frac{8}{15}-(\frac{8}{15}-\frac{7}{18})$
$=\frac{8}{15}-\frac{8}{15}+\frac{7}{18}$
$=0+\frac{7}{18}$
$=\frac{7}{18}$
$\frac{6}{7}+\frac{8}{11}+\frac{3}{11}$
$=\frac{6}{7}+(\frac{8}{11}+\frac{3}{11})$
$=\frac{6}{7}+1$
$=\frac{13}{7}$
$\frac{2}{3}-(\frac{2}{3}-\frac{1}{2})$
$=\frac{2}{3}-\frac{2}{3}+\frac{1}{2}$
$=0+\frac{1}{2}$
$=\frac{1}{2}$
$\frac{3}{4}-(\frac{1}{2}+\frac{1}{4})$
$=\frac{3}{4}-(\frac{2}{4}+\frac{1}{4})$
$=\frac{3}{4}-\frac{3}{4}$
$=0$

2.解方程。
$0.7x-1.8=0.3$
$3.5x+4.5x=24$
$x+\frac{1}{3}=\frac{1}{2}$
$0.7x-0.8=1.3$
$2x-\frac{1}{2}=\frac{1}{5}$
$4x-3x=26$

解：$0.7x - 1.8 = 0.3$
$0.7x = 0.3 + 1.8$
$0.7x = 2.1$
$x = 2.1÷0.7$
$x = 3$
解：$3.5x + 4.5x = 24$
$(3.5+4.5)x = 24$
$8x = 24$
$x = 24÷8$
$x = 3$
解：$x+\frac{1}{3}=\frac{1}{2}$
$x = \frac{1}{2}-\frac{1}{3}$
$x = \frac{3}{6}-\frac{2}{6}$
$x = \frac{1}{6}$
解：$0.7x - 0.8 = 1.3$
$0.7x = 1.3 + 0.8$
$0.7x = 2.1$
$x = 2.1÷0.7$
$x = 3$
解：$2x-\frac{1}{2}=\frac{1}{5}$
$2x = \frac{1}{5}+\frac{1}{2}$
$2x = \frac{2}{10}+\frac{5}{10}$
$2x = \frac{7}{10}$
$x = \frac{7}{10}÷2$
$x = \frac{7}{20}$
解：$4x - 3x = 26$
$(4-3)x = 26$
$x = 26$