This math topic focuses on practicing the concept of finding the lowest common denominator for the addition of fractions. It involves calculating which denominator is most suitable for adding two given fractions to simplify their sum. The skills are applied to various fraction addition problems, each presented in a different context but all requiring the identification of a common denominator. This is part of a broader unit on introductory mixed fraction addition and subtraction. Each question provides multiple choice answers, challenging the learner to select the correct common denominator from the options provided.