计算下面各题.①78÷5+78÷2 ②1.05×(3.8-0.8)÷6.3

2025-03-07 01:51:49
推荐回答(1个)
回答1:

7
8
÷5+
7
8
÷2,
=
7
8
×
1
5
+
7
8
×
1
2

=
7
8
×(
2
10
+
5
10
),
=
7
8
×
7
10

=
49
80



②1.05×(3.8-0.8)÷6.3,
=1.05×3÷6.3,
=3.15÷6.3,
=0.5;

1
4
×
2
5
+3÷4×
2
5

=
1
4
×
2
5
+
3
4
×
2
5

=
2
5
×(
1
4
+
3
4
),
=
2
5
×1,
=
2
5



3
4
+
3
7
÷
9
28
×
2
5

=④
3
4
+
3
7
×
28
9
×
2
5