第19页 - 初中数学七年级下册新课程自主学习与测评答案

141.28+(-27.64)+(-5)+84+(-16.8)+(-31.09)+125.7=270.45(万元)

答：合计本周收入270.45万元。

-8或-2

0

=

1.8

251.8

-180

-1

-q

$=-4\frac {1}{6}+8\frac {2}{5}-8\frac {1}{5}-2\frac {5}{6}-1\frac {3}{5}$

$=-(4 \frac {1}{6}+2 \frac {5}{6})+(8 \frac {2}{5}-8 \frac {1}{5}-1 \frac {3}{5})$

$=-7-1 \frac {2}{5}$

$=-8\frac {2}{5}$

$=4.5-2.5+9\frac {1}{3}-15\frac {2}{3}+2\frac {1}{3}$

$=(4.5-2.5)-(15 \frac {2}{3}-9 \frac {1}{3}-2 \frac {1}{3})$

$=2-4$

$=-2$