Question

9．$\frac{4}{5}$+$\frac{1}{5}$=$\frac{4}{5}$×$\frac{5}{4}$=$\frac{4}{5}$÷$\frac{4}{5}$=1$\frac{4}{5}$-$\frac{4}{5}$=1．

Answer 1

分析 根据乘除法及加减法的互逆关系解答即可．

解答 解：1-$\frac{4}{5}$=$\frac{1}{5}$
1÷$\frac{4}{5}$=$\frac{5}{4}$
$\frac{4}{5}$×1=$\frac{4}{5}$
1+$\frac{4}{5}$=1$\frac{4}{5}$
则$\frac{4}{5}$+$\frac{1}{5}$=$\frac{4}{5}$×$\frac{5}{4}$=$\frac{4}{5}$÷$\frac{4}{5}$=1$\frac{4}{5}$-$\frac{4}{5}$=1
故答案为：$\frac{1}{5}$，$\frac{5}{4}$，$\frac{4}{5}$，1$\frac{4}{5}$．

点评 此题考查了分数乘除法、减法的计算法则的运用．