第31页 - 通城学典课时作业本七年级数学苏科版江苏专用

C

10

相等

12

-20

解：原式$=\frac {10}{3}×(-\frac {6}{5})$

$=-4$

解：原式$=-\frac {8}{3}×(-\frac {9}{4})$

$=6$

解：原式$=0$

解：原式$=-\frac {15}{4}×(-\frac {10}{3})$

$=\frac {25}{2}$

解：原式$=-\frac {9}{4}×\frac {7}{4}×\frac {2}{3}×\frac {8}{7}$

$=-3$

解：原式$=\frac 12×\frac 23×\frac 94×(-\frac {16}{3})$

$=-4$

解：原式$ = (-\frac {2023}{2024}) × (-\frac {2022}{2023}) × (-\frac {2021}{2022}) ×(-\frac {2020}{2021})×··· × (-\frac {2}{3}) × (-\frac {1}{2})$

$=-\frac {2023}{2024}× \frac {2022}{2023} ×\frac {2021}{2022}×\frac {2020}{2021}×···×\frac {2}{3}×\frac {1}{2}$

$=-\frac {1}{2024}$