《2025年课时提优计划作业本七年级数学上册苏科版》

1. 计算：
(1)$12+(-2)+(-5)+8$；
(2)$-\frac{1}{2}-\left(+\frac{5}{4}\right)-\left(-\frac{3}{2}\right)+\left(-\frac{1}{4}\right)$；
(3)$(-81)÷ 2\frac{1}{4}× \left(-\frac{4}{9}\right)÷ 6$；
(4)$-15× \frac{2}{3}+\left(-\frac{3}{4}\right)÷ 0.125$；
(5)$1.25× (-3.2)÷ \left(0.5-\frac{2}{3}\right)÷ 2\frac{2}{3}$；
(6)$1+[20-(-8)]÷ (-4)$；
(7)$\left(1-1\frac{1}{2}-\frac{3}{8}+\frac{7}{12}\right)× (-24)$；
(8)$72× \frac{2}{9}+72÷ 1.5$；
(9)$49\frac{24}{25}× (-5)$；
(10)$3-\left(\frac{1}{3}-\frac{1}{6}-\frac{3}{4}\right)× (-24)$.

答案：
(1)原式=(12+8)+[(-2)+(-5)]=20-7=13.
(2)原式=$-\frac{1}{2}+(-\frac{5}{4})+\frac{3}{2}+(-\frac{1}{4})=(-\frac{1}{2}+\frac{3}{2})+[(-\frac{5}{4})+(-\frac{1}{4})]=1+(-\frac{3}{2})=-\frac{1}{2}$.
(3)原式=$81÷\frac{9}{4}×\frac{4}{9}÷6=81×\frac{4}{9}×\frac{4}{9}×\frac{1}{6}=\frac{8}{3}$.
(4)原式=$-10+(-\frac{3}{4})×8=-10-6=-16$.
(5)原式=$\frac{5}{4}×(-\frac{16}{5})÷(-\frac{1}{6})÷\frac{8}{3}=\frac{5}{4}×\frac{16}{5}×6×\frac{3}{8}=9$.
(6)原式=$1+28÷(-4)=1+(-7)=-6$.
(7)原式=$-24-\frac{3}{2}×(-24)-\frac{3}{8}×(-24)+\frac{7}{12}×(-24)=-24+36+9-14=7$.
(8)原式=$16+72÷\frac{3}{2}=16+72×\frac{2}{3}=16+48=64$.
(9)原式=$(50-\frac{1}{25})×(-5)=50×(-5)-\frac{1}{25}×(-5)=-250+\frac{1}{5}=-249\frac{4}{5}$.
(10)原式=$3-[\frac{1}{3}×(-24)-\frac{1}{6}×(-24)-\frac{3}{4}×(-24)]=3-(-8+4+18)=3-14=-11$.