Question

7．計(jì)算下面各題．
$\frac{16}{23}$×27+16×$\frac{19}{23}$；               $\frac{5}{12}$×28%×$\frac{4}{13}$；               12×99+12．

Answer 1

分析 ①$\frac{16}{23}$×27+16×$\frac{19}{23}$，將原式轉(zhuǎn)化為：$\frac{27}{23}×16+16×\frac{19}{23}$，再運(yùn)用乘法分配律簡算；   
②$\frac{5}{12}$×28%×$\frac{4}{13}$，首先把28%化成分?jǐn)?shù)是$\frac{7}{25}$，再根據(jù)分?jǐn)?shù)乘法的計(jì)算法則計(jì)算；  
③12×99+12，運(yùn)用乘法分配律簡算．

解答 解：①$\frac{16}{23}$×27+16×$\frac{19}{23}$
=$\frac{27}{23}×16+16×\frac{19}{23}$
=（$\frac{27}{23}+\frac{19}{23}$）×16
=2×16
=32；   

②$\frac{5}{12}$×28%×$\frac{4}{13}$
=$\frac{5}{12}×\frac{7}{25}×\frac{4}{13}$
=$\frac{7}{195}$；  

③12×99+12
=12×（99+1）
=12×100
=1200．

點(diǎn)評(píng) 此題考查的目的是理解掌握分?jǐn)?shù)、小數(shù)、整數(shù)四則混合運(yùn)算的順序以及它們的計(jì)算法則，并且能夠正確熟練地進(jìn)行計(jì)算．