Therefore, the total number of students in the seven-year class of this school is 24;
(2)24-6-4-6=8 (person),
The degree of the fan-shaped central angle of calligraphy is 8 ÷ 24× 360 =120;
Complete the bar chart as follows:
(3)480÷24×2
=20×2
=40 (name).
As a result, about 40 students won prizes throughout the school year.