(1)3÷
3
7 -
3
7 ÷3,
=3×
7
3 -
3
7 ×
1
3 ,
=7 -
1
7 ,
= 6
6
7 ;
(2)(
1
3 -
1
6 +
1
4 )×12,
=
1
3 ×12-
1
6 ×12+
1
4 ×12,
=4-2+3,
=5;
(3)
11
20 ÷[
1
2 ×(
2
3 +
4
5 )],
=
11
20 ÷[
1
2 ×
2
3 +
1
2 ×
4
5 ],
=
11
20 ÷[
1
3 +
2
5 ],
=
11
20 ×
15
11 ,
=
3
4 ;
(4)0.625×(8.3-2.5×12%),
=0.625×(8.3-0.3),
=
5
8 × 8,
=5;
(5)6.8×2.5+2.5×3.2,
=(6.8+3.2)×2.5,
=10×2.5,
=25;
(6)
7
4 ×
5
8 +
1
4 ÷
8
5
=
7
4 ×
5
8 +
1
4 ×
5
8 ,
=(
7
4 +
1
4 )×
5
8 ,
=
8
4 ×
5
8 ,
=
5
4 ,
= 1
1
4 .