《2025年优质课堂导学案七年级数学上册人教版》

1. (2024·张家口二模)计算$-8÷(-2)×(-\frac {1}{2})$的结果是(D)

A.8
B.-8
C.2
D.-2

答案： 1.D

2. 下列关系式不成立的是(C)

A.$\frac {-a}{b}=\frac {a}{-b}=-\frac {a}{b}$
B.$\frac {-a}{-b}=\frac {a}{b}$
C.若$a＜0,b＜0$,则$\frac {ab}{a+b}＞0$
D.若$a＞b,\frac {a}{b}＜0$,则$a＞0$

答案： 2.C

3. 下列计算正确的是(B)

A.$(-1)×2÷(-3)=-\frac {2}{3}$
B.$(-36)÷(-9)×1=4$
C.$(-4)÷\frac {1}{2}×(-2)=4$
D.$\frac {2}{3}×(-\frac {9}{2})÷(-2)=6$

答案： 3.B

4. (2024·花溪期中)在下列各式中,计算正确的是(C)

A.$-9÷6×\frac {1}{6}=-9$
B.$-\frac {3}{5}-\frac {5}{8}÷\frac {1}{2}=-3$
C.$-2÷(-4)-5=-4\frac {1}{2}$
D.$-15÷(-3×2)=-10$

答案： 4.C

5. 已知实数$a,b$在数轴上的位置如图所示,则$\frac {a}{|a|}· \frac {b}{|b|}$的值是(B)


A.-2
B.-1
C.0
D.2

答案： 5.B

6. 计算$(-7)×(-6)×0÷(-42)$的结果是0.

答案： 6.0

7. (2024·衡阳月考)计算:$-3\frac {4}{7}÷(-1\frac {2}{3})×(-4\frac {2}{3})=$-10.

答案： 7.-10

8. (2024·南海月考)计算$(-7)÷(-12)×\frac {1}{12}$的结果是(C)

A.-7
B.7
C.$\frac {7}{144}$
D.$-\frac {7}{144}$

答案： 8.C

9. 化简下列分数:
(1)$\frac {-42}{-7}=$6;
(2)$\frac {-\frac {1}{2}}{3}=$-\frac {1}{6};
(3)$\frac {0.3}{-\frac {1}{2}}=$-\frac {3}{5};
(4)$-\frac {-5}{-15}=$-\frac {1}{3}.

答案： $9.(1)6 (2)-\frac {1}{6} (3)-\frac {3}{5} (4)-\frac {1}{3}$

10. 计算:
(1)$-3\frac {1}{3}÷2\frac {1}{3}×(-2)$;
(2)$(-2\frac {4}{7})×(-1\frac {5}{6})÷|-1\frac {1}{21}|$;
(3)$32÷(-\frac {4}{5})×(-\frac {5}{4})÷(-2)$;
(4)$(-0.4)×(-\frac {4}{3})÷(-3\frac {2}{5})÷\frac {3}{17}$;
(5)$(-4\frac {1}{2})÷\frac {7}{25}×(-\frac {4}{3})×(-1\frac {2}{5})$;
(6)$3\frac {1}{7}×(3\frac {1}{7}÷7\frac {1}{3})×\frac {7}{22}÷|-1\frac {1}{21}|$.

答案： 10.
(1)解：原式$=\frac {10}{3}×\frac {3}{7}×2=\frac {20}{7}；$
(2)解：原式$=\frac {18}{7}×\frac {11}{6}×\frac {21}{22}=\frac {9}{2}；$
(3)解：原式$=-32×\frac {5}{4}×\frac {5}{4}×\frac {1}{2}=-25；$
(4)解：原式$=(-\frac {2}{5})×(-\frac {4}{3})×(-\frac {5}{17})×\frac {17}{3}=-(\frac {2}{5}×\frac {4}{3}×\frac {5}{17}×\frac {17}{3})=-\frac {8}{9}；$
(5)解：原式$=-\frac {9}{2}×\frac {25}{7}×(-\frac {4}{3})×(-\frac {7}{5})=-30；$
(6)解：原式$=\frac {22}{7}×\frac {22}{7}×\frac {3}{22}×\frac {7}{22}=\frac {9}{22}=\frac {3}{22}（$此处原书答案$\frac {9}{22}$疑似有误，按照计算应为$\frac{3}{22}？$按原书呈现$\frac {9}{22}）；$