①

1

3

+3÷

1

2

=6

1

3

②

1

12

×5×

12

17

=

5

17

③（

3

8

+

3

4

）×4=4

1

2

④81÷

9

5

=45，

⑤

1

2

-

1

4

=

1

4

⑥

1

5

×10=2 ⑦5.5+12.4+4.5=22.4 ⑧4-（0.6+1.9）=1.5，

⑨1.9×4×0.5=3.8 ⑩0.77+0.33=1.1，