6800毫升=升.
﹣ =
6﹣3.75=
6﹣ =
0.32=
÷6=
7× ÷7× =
( + )×4=
÷ =
①3.6+2.8+7.4+7.2
②( + + )×36
③2﹣ ×
④( + )÷ ﹣ .
(i)把图A按2:1的比放大.
(ii)把图B绕O点顺时针旋转90°.