①6.3×8.7+8.7×3.7

=（6.3+3.7）×8.7

=10×8.7

=87；

②（

1

3

-

1

6

+

1

4

）×12

=

1

3

×12-

1

6

×12+

1

4

×12

=4-2+3

=5；

③

7

4

×

5

8

+

1

4

÷

8

5

．

=

7

4

×

5

8

+

1

4

×

5

8

=（

7

4

+

1

4

）×

5

8

=2×

5

8

=1

1

4

．