Question

7．怎樣簡(jiǎn)便就怎樣計(jì)算
（$\frac{3}{5}$+$\frac{1}{6}$）×5×6
98×$\frac{96}{97}$
（15-14×$\frac{4}{7}$）×$\frac{8}{21}$
12.5%×25+$\frac{5}{8}$×15．

Answer 1

分析 ①用乘法分配律計(jì)算，（a+b）×c=ac+bc．
②用乘法分配律計(jì)算，ac+bc=（a+b）×c．
③先算加法再算減法，最后算除法．

解答 解：①（$\frac{3}{5}$+$\frac{1}{6}$）×5×6
=$\frac{3}{5}$×5×6+$\frac{1}{6}$×5×6
=18+5
=23

②98×$\frac{96}{97}$
=（97+1）×$\frac{96}{97}$
=$97×\frac{96}{97}+1×\frac{96}{97}$
=$96+\frac{96}{97}$
=$96\frac{96}{97}$

③（15-14×$\frac{4}{7}$）×$\frac{8}{21}$
=（15-8）×$\frac{8}{21}$
=$7×\frac{8}{21}$
=$\frac{8}{3}$

④12.5%×25+$\frac{5}{8}$×15
=$\frac{1}{8}×25+\frac{1}{8}×5×15$
=$\frac{1}{8}×（25+75）$
=$\frac{1}{8}×100$
=12.5

點(diǎn)評(píng) 本題考查了四則混合運(yùn)算的計(jì)算能力，注意小數(shù)、分?jǐn)?shù)之間的互化和約分．