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16页解析答案
计算:
(1)$-5+8-12+6$; (2)$2-[(-2)-(-4)]$;
(3)$7-(-6)+(-4)× (-3)$; (4)$\frac {3}{2}× (-\frac {1}{2})÷ (-4\frac {1}{2})$;
(5)$\frac {4}{3}× (-\frac {1}{6})-\frac {5}{3}÷ (-\frac {15}{7})$; (6)$-3× (-2)^{2}-1+(-\frac {1}{2})^{3}$;
(7)$-3^{2}+(-12)× |-\frac {1}{2}|-6÷ (-1)$; (8)$-2^{3}÷ (-\frac {1}{6})-\frac {1}{4}× (-2)^{2}$;
(9)$-4^{2}× |\frac {1}{2}-1|-(-5)+2$; (10)$25÷ \frac {5}{6}× (-\frac {2}{5})+(-2)× (-1)^{2024}$.
答案:(1)-3 (2)0 (3)25 (4)$\frac{1}{6}$ (5)$\frac{5}{9}$ (6)$-13\frac{1}{8}$ (7)-9 (8)47 (9)-1 (10)-14
解析:
(1) $-5 + 8 - 12 + 6 = (-5 - 12) + (8 + 6) = -17 + 14 = -3$
(2) $2 - [(-2) - (-4)] = 2 - (-2 + 4) = 2 - 2 = 0$
(3) $7 - (-6) + (-4)×(-3) = 7 + 6 + 12 = 25$
(4) $\frac{3}{2}×(-\frac{1}{2})÷(-4\frac{1}{2}) = \frac{3}{2}×(-\frac{1}{2})÷(-\frac{9}{2}) = \frac{3}{2}×(-\frac{1}{2})×(-\frac{2}{9}) = \frac{3×1×2}{2×2×9} = \frac{1}{6}$
(5) $\frac{4}{3}×(-\frac{1}{6}) - \frac{5}{3}÷(-\frac{15}{7}) = -\frac{2}{9} - \frac{5}{3}×(-\frac{7}{15}) = -\frac{2}{9} + \frac{7}{9} = \frac{5}{9}$
(6) $-3×(-2)^2 - 1 + (-\frac{1}{2})^3 = -3×4 - 1 + (-\frac{1}{8}) = -12 - 1 - \frac{1}{8} = -13\frac{1}{8}$
(7) $-3^2 + (-12)×|-\frac{1}{2}| - 6÷(-1) = -9 + (-12)×\frac{1}{2} + 6 = -9 - 6 + 6 = -9$
(8) $-2^3÷(-\frac{1}{6}) - \frac{1}{4}×(-2)^2 = -8×(-6) - \frac{1}{4}×4 = 48 - 1 = 47$
(9) $-4^2×|\frac{1}{2} - 1| - (-5) + 2 = -16×\frac{1}{2} + 5 + 2 = -8 + 5 + 2 = -1$
(10) $25÷\frac{5}{6}×(-\frac{2}{5}) + (-2)×(-1)^{2024} = 25×\frac{6}{5}×(-\frac{2}{5}) + (-2)×1 = 30×(-\frac{2}{5}) - 2 = -12 - 2 = -14$
上一页 下一页