(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 X×
8
5 =
15
2 ×
8
5 ,
X=12.