小学五年级数学问题:简单计算题:(2.17+5.49+3.81)*(5.49+2.17+9.2)-(3.81+2.17+5.49)

(2.17+5.49+3.81)*(5.49+2.17+9.2)-(3.81+2.17+5.49+9.2)*(2.17+5.49)

=(2.17+5.49+3.81)*(5.49+2.17)+(2.17+5.49+3.81)*9.2-(3.81+2.17+5.49)*(2.17+5.49)-9.2*(2.17+5.49)

=(2.17+5.49+3.81)*9.2-9.2*(2.17+5.49)