①(

1

4

-

1

2

+

1

6

)÷

1

12

=(

1

4

-

1

2

+

1

6

)×12

=

1

4

×12-

1

2

×12+

1

6

×12

=3-6+2

=-1；

            

②[(-5)2×(-

3

5

)+15]×(-2)3÷7

=[25×（-

3

5

）+15]×（-8）÷7

=[-15+15]×（-8）÷7

=0×（-8）÷7

=0．