Question

0.72除括号1.8除2.5括号

脱式计算：能简算就简算
6.42-2.8+3.58
1.26×0.72-0.26×0.72
12÷2.5÷0.4
5.1×[1.8÷（4.8-3.9）]
7.1×（1.2-0.2÷0.8）
[6.5+（2.8-1.3）]×0.4．

Answer 1

（1）6.42-2.8+3.58
=6.42+3.58-2.8
=10-2.8
=7.2

1.26×0.72-0.26×0.72
=（1.26-0.26）×0.72
=1×0.72
=0.72

12÷2.5÷0.4
=12÷（2.5×0.4）
=12÷1
=12

5.1×[1.8÷（4.8-3.9）]
=5.1×[1.8÷0.9]
=5.1×2
=10.2

7.1×（1.2-0.2÷0.8）
=7.1×（1.2-0.25）
=7.1×0.95
=6.745

[6.5+（2.8-1.3）]×0.4
=[6.5+1.5]×0.4
=8×0.4
=3.2