第32页 - 启东中学作业本七年级数学人教版

D

B

2

-10

$=-(2×7)+(6×9)$

$=-14+54$

$=40$

$=-4-6$

$=-10$

$=-28+3$

$=-25$

$=-4-6$

$=-10$

$=\frac {9}{4}×(-\frac {6}{7})÷(-\frac {3}{2})$

$=\frac {9}{4}×\frac {6}{7}×\frac {2}{3}$

$=\frac {9}{7}$

$=-\frac {2}{3}×\frac {1}{4}×\frac {1}{2}$

$=-\frac {1}{12}$

$=\frac {10}{3}×\frac {45}{4}×\frac {4}{27}×\frac {3}{10}$

$=\frac {5}{3}$

$=\frac {22}{7}×\frac {7}{22}×(\frac {22}{7}-\frac {22}{3})×\frac {21}{22}$

$=\frac {22}{7}×\frac {21}{22}-\frac {22}{3}×\frac {21}{22}$

$=3-7$

$=-4$

$=\frac {5}{4}×\frac {4}{5}×\frac {5}{4}×\frac {5}{4}$

$=\frac {25}{16}$

$=(-\frac {7}{8})÷(-\frac {7}{24})-\frac {7}{24}÷\frac {7}{8}$

$=3-\frac {1}{3}$

$=-2\frac {2}{3}$

D