In Chapter 9 of Class 5 Mathematics, students learn how to calculate the average by dividing the sum of values by the number of items. Various examples are solved, including numbers, weights, lengths, volumes, A’yah recited, pencils owned, student strength, cakes baked, and runs scored. Word problems reinforce the formula for finding averages, total quantities, and item counts. The review exercise includes multiple-choice questions and further practice problems, such as daily earnings and average of odd/even numbers. Key formulas and correct answers are provided to strengthen understanding of averages.