In crestview middle school12 out of 16 students are right handedif there 400 in the schoolhow many handed?

The fraction of right-handed students is 12/16, which simplifies to 3/4.

If there are 400 students in the school, the number of right-handed students is (3/4) * 400 = 300.

Therefore, there are $\boxed{300}$ right-handed students in Crestview Middle School.