①[3.2×(1-
5
8 )+3
3
5 ]×2
1
12 ,
=[3
1
5 ×(1-
5
8 )+3
3
5 ]×2
1
12 ,
=[3
1
5 ×
3
8 +3
3
5 ]×2
1
12 ,
=(
6
5 +
18
5 )×
25
12 ,
=
24
5 ×
25
12 ,
=10;
②1
3
7 +2
4
15 +4
4
7 +3
2
15 ,
=(1
3
7 +4
4
7 )+(2
4
15 +3
2
15 ),
=6+5
2
3 ,
=11
2
3 ;
③
43
97 ×99,
=
43
97 ×(97+2),
=
43
97 ×97+
43
97 ×2,
=43+
86
97 ,
=43
86
97 ;
④3.75×4
2
5 +1.6×3
3
4 ,
=3.75×4.4+1.6×3.75,
=3.75×(4.4+1.6),
=3.75×6,
=22.5;
⑤1÷2.5+2.5×0.4,
=0.4+2.5×0.4,
=0.4×(1+2.5),
=0.4×3.5,
=1.4;
⑥3
2
5 -1
3
4 -
1
4 ,
=3
2
5 -(1
3
4 +
1
4 ),
=3
2
5 -2,
= 1
2
5 .