30×

4

5

=24

2

5

÷

2

5

=1

5

4

×

4

5

÷

2

3

=

3

2

（

1

2

+

1

4

）×8=6

1

4

+

1

4

×3=1

1

7

+

2

7

×3=1

1

3

-

1

2

×

2

3

=0 6.3÷

1

10

=10