计算 21÷(1/3+2/5)÷9/11 2.23×2/5+2.77÷2.5 7/8÷[1/3×(3/2-3/4)].
问题描述:
计算
21÷(
+1 3
)÷2 5
9 11
2.23×
+2.77÷2.5 2 5
÷[7 8
×(1 3
-3 2
)]. 3 4
答
(1)21÷(
+1 3
)÷2 5
,9 11
=21÷
÷11 15
,9 11
=
÷315 11
,9 11
=35;
(2)2.23×
+2.77÷2.5,2 5
=0.892+1.108,
=2;
(3)
÷[7 8
×(1 3
-3 2
)],3 4
=
÷[7 8
×1 3
],3 4
=
÷7 8
,1 4
=3
.1 2