简便计算:12.4-12.4×0.25,0.25×9+1÷8.

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/14 14:44:32

简便计算:12.4-12.4×0.25,0.25×9+1÷8.

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

12.4-12.4×0.25

=12.4×1-12.4×1/4

=12.4×(1-1/4)

=12.4×3/4

=3.1×3

=9.3


0.25×9+1÷8

=1/4×9+1/8

=1/8×18+1/8×1

=1/8×(18+1)

=19/8  (8分之19)