1. 有理数的乘除混合运算步骤:(1)将除法运算转化为
2. 有理数的加减乘除混合运算,应先算
乘法
运算;(2)确定积的符号
;(3)通过约分求出结果.2. 有理数的加减乘除混合运算,应先算
乘除
,再算加减
,同级运算按从左
到右
的顺序计算,如果有括号,那么先做括号
内的运算.答案：1.(1)乘法 (2)符号 2.乘除 加减 左 右 括号
计算:
(1)$-4×\frac {1}{2}÷(-\frac {1}{2})×2;$ (2)$36÷4×(-\frac {1}{4})÷(-\frac {3}{2});$
(3)$(-35)÷\frac {5}{8}×(-\frac {3}{4})÷\frac {2}{3};$ (4)$-2.5÷\frac {5}{16}×(-\frac {1}{8})÷(-4);$
(5)$3×(-4)-(-28)÷7;$ (6)$-66×4-(-2.5)÷(-0.1);$
(7)$(-48)÷8-(-5)×(-6);$ (8)$(-\frac {6}{5})÷(-1\frac {1}{2})-(-\frac {3}{4})×1\frac {3}{5}.$
(1)$-4×\frac {1}{2}÷(-\frac {1}{2})×2;$ (2)$36÷4×(-\frac {1}{4})÷(-\frac {3}{2});$
(3)$(-35)÷\frac {5}{8}×(-\frac {3}{4})÷\frac {2}{3};$ (4)$-2.5÷\frac {5}{16}×(-\frac {1}{8})÷(-4);$
(5)$3×(-4)-(-28)÷7;$ (6)$-66×4-(-2.5)÷(-0.1);$
(7)$(-48)÷8-(-5)×(-6);$ (8)$(-\frac {6}{5})÷(-1\frac {1}{2})-(-\frac {3}{4})×1\frac {3}{5}.$
答案：解:(1)原式=-2×(-2)×2=8.
(2)原式=9×(-$\frac{1}{4}$)×(-$\frac{2}{3}$)=$\frac{3}{2}$.
(3)原式=35×$\frac{8}{5}$×$\frac{3}{4}$×$\frac{3}{2}$=63.
(4)原式=-$\frac{5}{2}$×$\frac{16}{5}$×$\frac{1}{8}$×$\frac{1}{4}$=-$\frac{1}{4}$.
(5)原式=-12+4=-8.
(6)原式=-264-25=-289.
(7)原式=-6-30=-36.
(8)原式=-$\frac{6}{5}$×(-$\frac{2}{3}$)+$\frac{3}{4}$×$\frac{8}{5}$=$\frac{4}{5}$+$\frac{6}{5}$=2.
(2)原式=9×(-$\frac{1}{4}$)×(-$\frac{2}{3}$)=$\frac{3}{2}$.
(3)原式=35×$\frac{8}{5}$×$\frac{3}{4}$×$\frac{3}{2}$=63.
(4)原式=-$\frac{5}{2}$×$\frac{16}{5}$×$\frac{1}{8}$×$\frac{1}{4}$=-$\frac{1}{4}$.
(5)原式=-12+4=-8.
(6)原式=-264-25=-289.
(7)原式=-6-30=-36.
(8)原式=-$\frac{6}{5}$×(-$\frac{2}{3}$)+$\frac{3}{4}$×$\frac{8}{5}$=$\frac{4}{5}$+$\frac{6}{5}$=2.