计算下列各题,能简算的要简算. 89×3/86 7/13÷4+6/13×1/4 1/20+0.24×6.4÷0.32 6-7/8×8/21-1/3.

问题描述:

计算下列各题,能简算的要简算.
89×

3
86
                                 
7
13
÷
4+
6
13
×
1
4

1
20
+0.24×6.4÷0.32                    
6-
7
8
×
8
21
-
1
3

(1)89×

3
86
 
=(86+3)×
3
86

=86×
3
86
+3×
3
86

=3+
9
86

=3
9
86

(2)
7
13
÷
4+
6
13
×
1
4

=
7
13
×
1
4
++
6
13
×
1
4

=(
7
13
+
6
13
)×
1
4

=1×
1
4

=
1
4

(3)
1
20
+0.24×6.4÷0.32
=0.05+0.24×(6.4÷0.32),
=0.05+0.24×20,
=0.05+4.8,
=4.85;
(4)6-
7
8
×
8
21
-
1
3

=6-
1
3
-
1
3

=5
1
3