《有理数凑整巧算》有理数凑整巧算

(-5$\frac {2}{5}$)+(-2$\frac {3}{5}$)=．

(-6$\frac {5}{6}$)+(-4$\frac {1}{6}$)=．

(-7$\frac {3}{4}$)+(-2$\frac {1}{4}$)=．

计算：12+(-7$\frac {1}{2}$)-(-18)-32.5=．

计算：6$\frac {3}{5}$+2-$\frac {1}{2}$-6.6=．(结果化成假分数．)

计算：$\frac {2}{5}$+$\frac {4}{7}$+[-$\frac {3}{5}$-($\frac {4}{5}$-$\frac {3}{7}$)]=．

(+1$\frac {1}{2}$)-(-2$\frac {1}{3}$)+(-$\frac {1}{2}$)-(+$\frac {2}{3}$)=．(结果化成假分数．)

计算：-4.2+5.7-8.4+10=．

计算 16+(-25)+24+(-35)=．