7. (1) $(-\frac{2}{3})-(+\frac{1}{3})-\left|-\frac{3}{4}\right|-(-\frac{1}{4}).$
(2) $\frac{1}{8}+[\frac{1}{3}-(\frac{1}{8}-\frac{2}{3})].$
(3) $-0.5+(-3\frac{1}{4})+(-1.75)+(7\frac{1}{2}).$
(4) $(-4\frac{1}{5})-(+3\frac{1}{4})-(-\frac{1}{4})-(-4\frac{1}{5}).$
8. $(-1.4)-(+2\frac{2}{3})-(-1\frac{2}{5})+(-3.2).$
9. $21\frac{1}{2}+(-36\frac{2}{7})-(+16\frac{1}{2})+(+45\frac{4}{7})-(-10\frac{5}{7}).$

7. (1) $-1\frac{1}{2}$.
(2) 1.
(3) 2.
(4) -3.
8. $-5\frac{13}{15}$.
9. 25.

10.某储蓄所办理了七笔储蓄业务，取出9.5万元，存进5万元，取出8万元，存进12万元，存进25万元，取出10.5万元，取出2万元，这时这个储蓄所的现金增加多少万元？

10. $-9.5-10.5-8-2+5+25+12=12$(万元).