解:原式=2.5*0.4*0.8*12.5=1*10=10
=2.5x4x0.8x12.5=10x0.08x12.5=0.8x12.5=10
2.5×0.32×12.5=2.5×0.4×0.8×12.5=1×10=10
5.1×O.O8×12.5
0.32×12.5