This math topic focuses on the skill of finding the lowest common denominator for the purpose of adding fractions. Each question presents a pair of fractions for which students need to identify the appropriate lowest common denominator from multiple-choice answers. The skill practiced is essential for fraction addition and involves changing the denominators of the fractions to facilitate their combination. This is part of a broader unit on fraction addition and subtraction with mixed practice, designed to help students master the basics of working with fractions.