2.5×7.2÷（冲森哗春老0.9÷4）=2.5×7.2÷0.9×4=（散行2.5×4）×（7.2÷0.9）=10×8=80
=(2.5x4)x(7.2÷0.9)x4=10x8=80
2.5×4×(7.2÷0.9)＝10×8＝80
=2.5×7.2÷0.9×4 =10×8 =80
