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1.计算$24÷(-4)×3$的结果是（
A.$-18$
B.$18$
C.$-2$
D.$2$
A
）A.$-18$
B.$18$
C.$-2$
D.$2$
答案
A
2. 计算$(-3)×\frac{1}{3}÷(-3)×3$的结果是（
A.－1
B.1
C.3
D.－3
B
）A.－1
B.1
C.3
D.－3
答案
B
3. 下列运算正确的是 （
A.$2÷(-\dfrac{2}{3})×(-\dfrac{3}{4})=2×\dfrac{3}{2}×\dfrac{4}{3}=4$
B.$(-2)÷\dfrac{1}{5}×(-5)=(-2)÷(-1)=2$
C.$2÷(-4)÷\dfrac{1}{2}=2×(-\dfrac{1}{4})×2=-1$
D.$8÷(4-\dfrac{1}{4})=8÷4 -8÷\dfrac{1}{4}=2-32=-30$
C
）A.$2÷(-\dfrac{2}{3})×(-\dfrac{3}{4})=2×\dfrac{3}{2}×\dfrac{4}{3}=4$
B.$(-2)÷\dfrac{1}{5}×(-5)=(-2)÷(-1)=2$
C.$2÷(-4)÷\dfrac{1}{2}=2×(-\dfrac{1}{4})×2=-1$
D.$8÷(4-\dfrac{1}{4})=8÷4 -8÷\dfrac{1}{4}=2-32=-30$
答案
C
4.填空：$6÷\frac{2}{3}×\frac{3}{2}=6×$
$\frac{3}{2}$
$×\frac{3}{2}=$ $\frac{27}{2}$
.答案
$\frac{3}{2}$，$\frac{27}{2}$
5.计算:
(1)$2÷ \dfrac{1}{5}× (-5)$；
(2)$(-12)× (-\dfrac{1}{4})÷ (-\dfrac{6}{5})$；
(3)$(-\dfrac{3}{4})÷ \dfrac{5}{4}÷ (-\dfrac{3}{10})$；
(4)$-2.5÷ (-\dfrac{4}{3})÷ \dfrac{5}{8}$。
(1)$2÷ \dfrac{1}{5}× (-5)$；
(2)$(-12)× (-\dfrac{1}{4})÷ (-\dfrac{6}{5})$；
(3)$(-\dfrac{3}{4})÷ \dfrac{5}{4}÷ (-\dfrac{3}{10})$；
(4)$-2.5÷ (-\dfrac{4}{3})÷ \dfrac{5}{8}$。
答案
(1)$-50$ (2)$-\frac{5}{2}$ (3)$2$ (4)$3$
6. 计算:
(1)$(-15)÷(-3)×(+\dfrac{2}{5});$
(2)$(-\dfrac{1}{2})×(-8)÷(-\dfrac{2}{3});$
(3)$8÷(-\dfrac{5}{7})×\dfrac{2}{7}÷(-\dfrac{4}{5});$
(4)$25÷(-5)×\dfrac{1}{5}÷(-\dfrac{3}{4}).$
(1)$(-15)÷(-3)×(+\dfrac{2}{5});$
(2)$(-\dfrac{1}{2})×(-8)÷(-\dfrac{2}{3});$
(3)$8÷(-\dfrac{5}{7})×\dfrac{2}{7}÷(-\dfrac{4}{5});$
(4)$25÷(-5)×\dfrac{1}{5}÷(-\dfrac{3}{4}).$
答案
(1)$2$ (2)$-6$ (3)$4$ (4)$\frac{4}{3}$
