用简便方法计算. 5/12×1/13-1/4÷13 3.5×98+35×0.2.

问题描述:

用简便方法计算.

5
12
×
1
13
-
1
4
÷13                      
3.5×98+35×0.2.

5
12
×
1
13
-
1
4
÷13   
=
5
12
×
1
13
-
1
4
×
1
13

=(
5
12
-
1
4
)×
1
13

=
1
6
×
1
13
   
=
1
78

                
②3.5×98+35×0.2
=35×9.8+35×0.2
=35×(9.8+0.2)
=35×10
=350