①25.3×12-33.46÷0.35 

=303.6-95.6

=208；

②12.74-0.125+2.26-9.875    

=（12.74+2.26）-（0.125+9.875）

=15-10

=10；

③（

3

8

+

5

6

）÷

1

24

=（

3

8

+

5

6

）×24

=

3

8

×24+

5

6

×24

=9+20

=29；

④2.5×13×0.4 

=2.5×0.4×13

=1×13

=13；

⑤

8

9

÷[（

2

5

+

1

10

）×

3

4

]

=

8

9

÷（

1

2

×

3

4

）

=

8

9

÷

3

8

=

8

9

×

8

3

=

64

27

；

⑥

4

5

+

4

5

×19

=（1+19）×

4

5

=20×

4

5

=16．