混合数的运算

例子:

$\begin{array}{l}3.\frac{2}{5}+4\frac{1}{5}＝\frac{17}{5}+\frac{21}{5}\\ ＝\frac{（17+21）}{5}\\ ＝\frac{38}{5}\text{或}7\frac{3.}{5}\end{array}$

注意:你可以用另一种方法把带分数相加。首先，将整数部分相加，然后分别将分数部分相加。然后把答案写成最简形式。例如:

$\begin{array}{l}3.\frac{2}{5}+4\frac{1}{5}＝（3.+4）+（\frac{2}{5}+\frac{1}{5}）\\ ＝7+\frac{2+1}{5}\\ ＝7+\frac{3.}{5}\\ ＝7\frac{3.}{5}\end{array}$

例子:

$\begin{array}{l}9\frac{1}{6}-5\frac{2}{6}＝\frac{55}{6}-\frac{32}{6}\\ ＝\frac{55-32}{6}\\ ＝\frac{23}{6}\text{或}3.\frac{5}{6}\end{array}$

例子:

$\begin{array}{l}2\frac{2}{3.}\cdot 3.\frac{1}{5}＝\frac{8}{3.}\cdot \frac{16}{5}\\ ＝\frac{128}{15}\\ ＝8\frac{8}{15}\end{array}$

例子:

$3.\frac{1}{2}÷4\frac{2}{3.}＝\frac{7}{2}÷\frac{14}{3.}$

的乘法逆$\frac{14}{3.}$是$\frac{3.}{14}$．

$\begin{array}{l}＝\frac{7}{2}\cdot \frac{3.}{14}\\ ＝\frac{21}{28}\\ ＝\frac{3.}{4}\end{array}$