计算下面各题,怎样简便就怎样计算.(1) 5 7 + 3 4 + 2 7 + 1 4

2024-11-19 04:59:24
推荐回答(1个)
回答1:

(1)
5
7
+
3
4
+
2
7
+
1
4

=(
5
7
+
2
7
)+(
3
4
+
1
4
),
=1+1,
=2;

(2)
5
9
×
2
3
+
4
9
÷
3
2

=
2
3
×(
5
9
+
4
9
),
=
2
3
×1,
=
2
3


(3)
15
16
÷
[
7
8
-
3
8
+
1
8
)],
=
15
16
÷
[
7
8
-
1
2
].
=
15
16
÷
3
8

=2
1
2