Question

9．計算題．

$\frac{12}{13}$×$\frac{5}{8}$÷$\frac{15}{26}$	$\frac{13}{75}$÷$\frac{39}{25}$÷$\frac{4}{5}$	$\frac{49}{4}$÷$\frac{3}{2}$×$\frac{3}{7}$
$\frac{5}{8}$÷$\frac{10}{7}$÷$\frac{7}{10}$	$\frac{6}{5}$×$\frac{2}{3}$×$\frac{5}{18}$	$\frac{1}{5}$×$\frac{1}{50}$÷$\frac{1}{500}$．

Answer 1

分析 ①把除法變成乘法，先約分再計算．
②把除法變成乘法，先約分再計算．
③把除法變成乘法，先算$\frac{49}{4}×\frac{3}{7}$，再乘$\frac{2}{3}$．
④把除法變成乘法，先約分再計算．
⑤先算第一個乘第三個，然后再乘第二個．
⑥把除法變成乘法，先算前兩個，再和第三個相乘．

解答 解：①$\frac{12}{13}$×$\frac{5}{8}$÷$\frac{15}{26}$
=$\frac{12}{13}$×$\frac{5}{8}$×$\frac{26}{15}$
=1

②$\frac{13}{75}$÷$\frac{39}{25}$÷$\frac{4}{5}$
=$\frac{13}{75}×\frac{25}{39}×\frac{5}{4}$
=$\frac{1}{9}$×$\frac{5}{4}$
=$\frac{5}{36}$

③$\frac{49}{4}$÷$\frac{3}{2}$×$\frac{3}{7}$
=$\frac{49}{4}×\frac{3}{7}×\frac{2}{3}$
=$\frac{7}{2}$

④$\frac{5}{8}$÷$\frac{10}{7}$÷$\frac{7}{10}$
=$\frac{5}{8}×\frac{7}{10}×\frac{10}{7}$
=$\frac{5}{8}×1$
=$\frac{5}{8}$

⑤$\frac{6}{5}$×$\frac{2}{3}$×$\frac{5}{18}$
=$\frac{4}{5}×\frac{5}{18}$
=$\frac{2}{9}$

⑥$\frac{1}{5}$×$\frac{1}{50}$÷$\frac{1}{500}$
=$\frac{1}{250}×\frac{500}{1}$
=2

點評 本題主要考查分數(shù)四則混合運算的計算順序．