Question

15．口算．

$\frac{4}{15}+\frac{7}{15}$=	$\frac{9}{11}-\frac{7}{11}$=	$\frac{5}{12}+\frac{7}{12}$=	$\frac{5}{6}-\frac{1}{6}$=
$\frac{9}{19}+\frac{4}{19}$=	$\frac{9}{16}-\frac{3}{16}$=	$\frac{1}{3}-\frac{1}{7}$=	$\frac{1}{6}-\frac{1}{7}$=
$\frac{1}{5}-\frac{1}{8}$=	$\frac{1}{8}+\frac{1}{9}$=	$\frac{1}{2}+\frac{1}{5}$=	$\frac{1}{4}+\frac{1}{5}$=

Answer 1

分析 根據(jù)分?jǐn)?shù)加減法的計(jì)算法則進(jìn)行計(jì)算即可．

解答 解：

$\frac{4}{15}+\frac{7}{15}$=$\frac{11}{15}$	$\frac{9}{11}-\frac{7}{11}$=$\frac{2}{11}$	$\frac{5}{12}+\frac{7}{12}$=1	$\frac{5}{6}-\frac{1}{6}$=$\frac{2}{3}$
$\frac{9}{19}+\frac{4}{19}$=$\frac{13}{19}$	$\frac{9}{16}-\frac{3}{16}$=$\frac{3}{8}$	$\frac{1}{3}-\frac{1}{7}$=$\frac{4}{21}$	$\frac{1}{6}-\frac{1}{7}$=$\frac{1}{42}$
$\frac{1}{5}-\frac{1}{8}$=$\frac{3}{40}$	$\frac{1}{8}+\frac{1}{9}$=$\frac{17}{72}$	$\frac{1}{2}+\frac{1}{5}$=$\frac{7}{10}$	$\frac{1}{4}+\frac{1}{5}$=$\frac{9}{20}$

點(diǎn)評(píng) 此題考查了分?jǐn)?shù)加減法的計(jì)算法則的運(yùn)用．