零五网 全部参考答案 启东中学作业本 2025年启东中学作业本七年级数学上册人教版 第17页解析答案
计算:
(1)$-4^{2}+2×(-3)^{2}-(-6)÷(-\frac {4}{3})$; (2)$[(-3)^{2}-(-0.75)×\frac {8}{3}-19]×(-4)$;
(3)$-1^{4}+(-2)÷(-\frac {1}{3})-|-9|$; (4)$(-1)^{10}÷2+(-\frac {1}{2})^{3}×16$;
(5)$[1\frac {1}{4}-(\frac {3}{8}+\frac {1}{6}-\frac {3}{4})×24]÷5$; (6)$-3^{2}÷3-[(-2)×(-\frac {3}{4})+(-\frac {1}{2})]^{3}$;
(7)$[1-(1-0.5×\frac {1}{3})]×[2-(-3)^{2}]$; (8)$16÷(-2)^{3}÷\frac {(-5)^{2}}{2}×(-4)+(-1)^{2023}$.
答案:(1)-2.5 (2)32 (3)-4 (4)-1.5 (5)$1\frac{1}{4}$ (6)-4 (7)$-\frac{7}{6}$ (8)$-\frac{9}{25}$
解析:
(1) $-4^{2}+2×(-3)^{2}-(-6)÷(-\frac {4}{3})$
$=-16 + 2×9 - (-6)×(-\frac{3}{4})$
$=-16 + 18 - \frac{9}{2}$
$=2 - 4.5$
$=-2.5$
(2) $[(-3)^{2}-(-0.75)×\frac {8}{3}-19]×(-4)$
$=[9 - (-\frac{3}{4})×\frac{8}{3} - 19]×(-4)$
$=[9 + 2 - 19]×(-4)$
$=(-8)×(-4)$
$=32$
(3) $-1^{4}+(-2)÷(-\frac {1}{3})-|-9|$
$=-1 + (-2)×(-3) - 9$
$=-1 + 6 - 9$
$=5 - 9$
$=-4$
(4) $(-1)^{10}÷2+(-\frac {1}{2})^{3}×16$
$=1÷2 + (-\frac{1}{8})×16$
$=\frac{1}{2} - 2$
$=-1.5$
(5) $[1\frac {1}{4}-(\frac {3}{8}+\frac {1}{6}-\frac {3}{4})×24]÷5$
$=[\frac{5}{4} - (\frac{3}{8}×24 + \frac{1}{6}×24 - \frac{3}{4}×24)]÷5$
$=[\frac{5}{4} - (9 + 4 - 18)]÷5$
$=[\frac{5}{4} - (-5)]÷5$
$=(\frac{5}{4} + 5)÷5$
$=(\frac{5}{4} + \frac{20}{4})×\frac{1}{5}$
$=\frac{25}{4}×\frac{1}{5}$
$=\frac{5}{4}$
$=1\frac{1}{4}$
(6) $-3^{2}÷3-[(-2)×(-\frac {3}{4})+(-\frac {1}{2})]^{3}$
$=-9÷3 - [\frac{3}{2} - \frac{1}{2}]^{3}$
$=-3 - [1]^{3}$
$=-3 - 1$
$=-4$
(7) $[1-(1-0.5×\frac {1}{3})]×[2-(-3)^{2}]$
$=[1 - (1 - \frac{1}{2}×\frac{1}{3})]×[2 - 9]$
$=[1 - (1 - \frac{1}{6})]×(-7)$
$=[1 - \frac{5}{6}]×(-7)$
$=\frac{1}{6}×(-7)$
$=-\frac{7}{6}$
(8) $16÷(-2)^{3}÷\frac {(-5)^{2}}{2}×(-4)+(-1)^{2023}$
$=16÷(-8)÷\frac{25}{2}×(-4) + (-1)$
$=16×(-\frac{1}{8})×\frac{2}{25}×(-4) - 1$
$=(-2)×\frac{2}{25}×(-4) - 1$
$=(-\frac{4}{25})×(-4) - 1$
$=\frac{16}{25} - 1$
$=-\frac{9}{25}$
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