问题 解答题
计算下列各题.(能简算的写出简算过程)
1
8
+
5
7
+6.875+
2
7
7
9
÷
11
5
+
2
9
×
5
11
1
3
÷(
2
3
-
2
5
)×
3
5
1
2
-(
3
4
-
3
5
)〕÷
7
10
1
8
X-1=0.2
X:
5
14
=21:
5
8
答案

(1)

1
8
+
5
7
+6.875+
2
7

=(

1
8
+6.875)+(
2
7
+
5
7
),

=(0.125+6.875)+1,

=7+1,

=8;

(2)

7
9
÷
11
5
+
2
9
×
5
11

=

7
9
×
5
11
+
2
9
×
5
11

=(

7
9
+
2
9
)×
5
11

=1×

5
11

=

5
11

(3)

1
3
÷(
2
3
-
2
5
)×
3
5

=

1
3
÷
4
15
×
3
5

=

1
3
×
15
4
×
3
5

=

3
4

(4)[

1
2
-(
3
4
-
3
5
)]÷
7
10

=[

1
2
-
3
20
7
10

=

7
20
×
10
7

=

1
2

(5)

1
8
X-1=0.2,

1
8
X-1+1=0.2+1,

1
8
X=1.2,

1
8
X×8=1.2×8,

X=9.6;

(6)X:

5
14
=21:
5
8

5
8
X=
5
14
×21,

5
8
X=
15
2

5
8
8
5
=
15
2
×
8
5

X=12.

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