(1) (
1
18 -
1
54 )÷
1
54 ,
=(
1
18 -
1
54 )×54,
=
1
18 ×54 -
1
54 ×54,
=3-1,
=2,
(2)
7
8 × 43+
7
8 ×36+
7
8 ,
=
7
8 ×(43+36+1),
=
7
8 ×80,
=70,
(3))
5
9 ×(
3
4 ÷
1
10 ) ,
=
5
9 ×(
3
4 ×10),
=
5
9 ×
15
2 ,
= 4
1
6 ,
(4))
8
15 ÷[
1
25 ×(
2
5 +
1
10 )] ,
=
8
15 ÷(
1
25 ×
1
2 ),
=
8
15 ÷
1
50 ,
= 26
2
3 .