第25页 - 亮点给力提优课时作业本七年级数学江苏版

D

－1

302

$28\frac{3}{8}\ $

$ \begin{aligned}解：原式&= [(－3\frac{1}{2})+2\frac{1}{2}]+[(-4\frac{1}{3})+ (－4\frac{2}{3}) \\ &=-1+(-9) \\ &=-10 \\ \end{aligned}$

C

0

$a+b$

$解：原式=[(－2024)+(－\frac {5}{6})]+[(－2023)+(－\frac {2}{3})]+(4048+\frac {2}{3})+[(－1)+(－\frac {2}{3})]$

$=[(－2024)+(－2023)+4048+(－1)]+[(－\frac {5}{6})+(－\frac {2}{3})+\frac {2}{3}+(－\frac {1}{2})]$

$=0+(－\frac {4}{3})$

$=－\frac {4}{3}$

$ \begin{aligned}解：原式&=[1\frac{3}{4}+(-1.75)]+(3\frac{3}{8}+2\frac{5}{8})+ (-6.5) \\ &=0+6+(-6.5) \\ &=－0.5. \\ \end{aligned}$