问题 解答题
①45×8-240÷15
②(2.5-2.5×0.6)÷0.4
③41.2-9.5×1.8÷0.45
④(
1
4
+
1
9
-
1
12
)×72
8
15
÷
1
6
-
7
15
×6
7
10
÷[(
3
5
-
1
4
)×12].
答案

①45×8-240÷15,

=360-16,

=344;

②(2.5-2.5×0.6)÷0.4,

=(2.5-1.5)÷0.4

=1÷0.4,

=2.5;

③41.2-9.5×1.8÷0.45,

=41.2-17.1÷0.45,

=41.2-38,

=3.2;

④(

1
4
+
1
9
-
1
12
)×72,

=

1
4
×72+
1
9
×72-
1
12
×72,

=18+8-6,

=26-6,

=20;

8
15
÷
1
6
-
7
15
×6,

=

8
15
×6+
7
15
×6,

=(

8
15
+
7
15
)×6,

=1×6,

=6;

7
10
÷[(
3
5
-
1
4
)×12],

=

7
10
÷[
7
20
×12],

=

7
10
÷
21
5

=

7
10
×
5
21

=

1
6

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