Question

6．計(jì)算：97$\frac{1}{50}$×$\frac{1}{49}$+77$\frac{1}{40}$×$\frac{1}{39}$+57$\frac{1}{30}$×$\frac{1}{29}$．

Answer 1

分析 97$\frac{1}{50}$=98-$\frac{49}{50}$，77$\frac{1}{40}$=78-$\frac{39}{40}$，57$\frac{1}{30}$=58-$\frac{29}{30}$，然后再根據(jù)乘法分配律進(jìn)行簡算．

解答 解：97$\frac{1}{50}$×$\frac{1}{49}$+77$\frac{1}{40}$×$\frac{1}{39}$+57$\frac{1}{30}$×$\frac{1}{29}$
=（98-$\frac{49}{50}$）×$\frac{1}{49}$+（78-$\frac{39}{40}$）×$\frac{1}{39}$+（58-$\frac{29}{30}$）×$\frac{1}{29}$
=98×$\frac{1}{49}$-$\frac{49}{50}$×$\frac{1}{49}$+78×$\frac{1}{39}$-$\frac{39}{40}$×$\frac{1}{39}$+58×$\frac{1}{29}$-$\frac{29}{30}$×$\frac{1}{29}$
=2-$\frac{1}{50}$+2-$\frac{1}{40}$+2-$\frac{1}{30}$
=（2+2+2）-（$\frac{1}{50}$+$\frac{1}{40}$+$\frac{1}{30}$）
=6-$\frac{47}{600}$
=5$\frac{553}{600}$．

點(diǎn)評(píng) 考查了運(yùn)算定律與簡便運(yùn)算，四則混合運(yùn)算．注意運(yùn)算順序和運(yùn)算法則，靈活運(yùn)用所學(xué)的運(yùn)算定律簡便計(jì)算．