简便计算：12.4-12.4×0.25,0.25×9+1÷8.
问题描述：
简便计算：12.4-12.4×0.25,0.25×9+1÷8.
答
12.4-12.4*0.25
=3.1*4 - 3.1*4*0.25
=3.1*4 - 3.1*(4*0.25)
=3.1*4-3.1
=3.1*(4-1)
=3.1*3
=9.3
0.25*9+1÷8
=(0.25*9*8 + 1÷8*8) ÷ 8
=(0.25*4*9*2 + 1)÷8
=(18+1)÷8
=19÷8
=2.375