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
÷15=3 7
40-(7.7+4.8÷1.2)
(
+3 29
)×13×29= 1 13
答
(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
÷15,3 7
=
÷3 2
÷15,3 7
=
÷15,7 2
=
;7 30
(3)40-(7.7+4.8÷1.2),
=40-(7.7+4),
=40-11.7,
=28.3;
(4)(
+3 29
)×13×29,1 13
=
×13×29+3 29
×13×29,1 13
=39+29,
=68.