2.5×(2.8×0.04)
=2.5*4*2.8/100
=28/100
=0.28
（8×2.57）×1.25
=8*1.25*2.57
=10*2.57
=25.7
36×0.25+64×0.25
=(36+64)*0.25
=100*0.25
=25
0.04×29+0.04*71
=0.04*(29+71)
=0.04*100
=4