18.76乘9.9加1.876
=18.76*9.9+18.76*0.1
=18.76*(9.9+0.1)
=18.76*10
=187.6
15.7除以（15.7除以0.4）
=15.7除以（15.7/0.4）
=15.7 *（0.4/15.7）
=0.4
12.8乘17.5减1.28乘75
=12.8*17.5-12.8*7.5
=12.8*(17.5-7.5)
=12.8*10
=128
32.4乘4减2.4除以0.5
=32.4*4-2.4*2
=32.4*4-1.2*4
=(32.4-1.2)*4
=31.2*4
=124.8