①（

7

10

-

1

6

+

2

5

）÷

1

30

，

=（

7

10

-

1

6

+

2

5

）×30，

=

7

10

×30-

1

6

×30+

2

5

×30，

=21-5+12，

=16+12，

=28；

②74×

9

25

+2.6×3.6，

=74×0.36+2.6×3.6，

=7.4×3.6+2.6×3.6，

=（7.4+2.6）×3.6，

=10×3.6，

=36．