问题 解答题
怎样简便怎样算
2
7
+
1
5
)×35
8
9
×[
3
4
-(
7
16
-
1
4
)]
1
13
+
12
13
×(
5
2
-
1
3
3.5×72+65×7.2120÷[4.5×(1-
8
9
)]
11
15
-(
3
5
-
4
15
答案

(1)(

2
7
+
1
5
)×35,

=

2
7
×35+
1
5
×35,

=10+7,

=17;

(2)

8
9
×[
3
4
-(
7
16
-
1
4
)],

=

8
9
×[
3
4
-(
7
16
-
4
16
)],

=

8
9
×[
3
4
-
3
16
],

=

8
9
×[
12
16
-
3
16
],

=

8
9
×
9
16

=

1
2

(3)

1
13
+
12
13
×(
5
2
-
1
3
),

=

1
13
+
12
13
×(
15
6
-
2
6
),

=

1
13
+
12
13
×
13
6

=

1
13
+2,

=2

1
13

(4)3.5×72+65×7.2,

=35×7.2+65×7.2,

=(35+65)×7.2,

=100×7.2,

=720;

(5)120÷[4.5×(1-

8
9
)],

=120÷[4.5×

1
9
],

=120÷0.5,

=240;

(6)

11
15
-(
3
5
-
4
15
),

=

11
15
-
3
5
+
4
15

=(

11
15
+
4
15
)-
3
5

=1-

3
5

=

2
5

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