(1)
4
15 ×75,
=
4
15 ×(15×5),
=(
4
15 ×15)×5,
=4×5,
=20;
(2)
7
18 ×
9
14 =
1
4 ;
(3)
9
14 ×21×
2
9 ,
=
27
2 ×
2
9 ,
=3;
(4)
11
14 ×
7
10 ×
8
33 ,
=
11
20 ×
8
33 ,
=
2
15 ;
(5)
3
4 ×
2
5 +
3
5 ×
3
4 ,
=
3
4 ×(
2
5 +
3
5 ),
=
3
4 ;
(6)
4
5 ×
5
8 +
5
12 ×
4
5 ,
=
1
2 +
1
3 ,
=
5
6 ;
(7)
9
20 ×(
2
3 -
3
7 ),
=
9
20 ×
5
21 ,
=
3
28 ;
(8)(
5
6 +
5
8 )×
8
25 ,
=
5
6 ×
8
25 +
5
8 ×
8
25 ,
=
4
15 +
1
5 ,
=
7
15 .