问题 解答题
计算.
0.25×[(2.8+4.4)÷1.2]
14
15
×
1
4
-
2
15
÷4
3
5
÷[(
7
9
+
1
3
)×
3
2
]
3
7
×
1
3
+
4
7
÷3.
答案

(1)0.25×[(2.8+4.4)÷1.2]

=0.25×[7.2÷1.2]

=0.25×6

=1.5;

(2)

14
15
×
1
4
-
2
15
÷4

=

14
15
×
1
4
-
2
15
×
1
4

=(

14
15
-
2
15
)×
1
4

=

12
15
×
1
4

=

1
5

(3)

3
5
÷[(
7
9
+
1
3
)×
3
2
]

=

3
5
÷[
10
9
×
3
2
]

=

3
5
×
3
5

=

9
25

(4)

3
7
×
1
3
+
4
7
÷3

=

3
7
×
1
3
+
4
7
×
1
3

=(

3
7
+
4
7
)×
1
3

=

1
3

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