The title is:

(1) Find the total number of students in each class: (i) Class I: 28 + 23 = 51 students (ii) Class II: 20 + 24 = 44 students (iii) Class III: 18 + 27 = 45 students (iv) Class IV: 26 + 23 = 49 students (v) Class V: 24 + 21 = 45 students.