4 + 7 = 11 students
9 - 4 = 5 students
7 - 4 + 3 students
3 + 4 = 7 students
4 + 4 = 8 students
4 - 3 = 1 student
213, 734, 923, 11, 209
198, 290, 381, 426, 721
198, 721, 462, 381, 290
721, 426, 381, 290, 198