2013乘于八分之三减零点三七五乘于一千九百五十二加三点七五乘于一点九=2013*(3/8)-0.375*1952+3.75*1.9=2013*0.375-0.375*1952+0.375*19=0.375(2013-1952+19)=0.375*80=30
