计算下列各题.(能简算的要简算) 3.8-1.9+7.2-8.1 (7/8+5/8)÷3/7÷15= 40-(7.7+4.8÷1.2) (3/29+1/13)×13×29=

问题描述:

计算下列各题.(能简算的要简算)
3.8-1.9+7.2-8.1

7
8
+
5
8
)÷
3
7
÷15=
40-(7.7+4.8÷1.2)
3
29
+
1
13
)×13×29=


(1)3.8-1.9+7.2-8.1,
=(3.8+7.2)-(1.9+8.1),
=11-10,
=1;
(2)(

7
8
+
5
8
)÷
3
7
÷15,
=
3
2
÷
3
7
÷15,
=
7
2
÷15,
=
7
30

(3)40-(7.7+4.8÷1.2),
=40-(7.7+4),
=40-11.7,
=28.3;
(4)(
3
29
+
1
13
)×13×29,
=
3
29
×13×29+
1
13
×13×29,
=39+29,
=68.