This resource focuses on enhancing students' mental math skills, particularly in mental addition and subtraction of 3-digit numbers. Through a structured approach, students will learn to decompose numbers into hundreds, tens, and ones for efficient calculations. The document includes a strategy review with a detailed example to illustrate the decomposition method. Following this, there is independent practice where students solve various addition and subtraction problems while demonstrating their mental steps. Additionally, there is a Quick-Recall Subtraction Challenge that encourages students to employ strategies such as related equations and benchmark numbers to solve subtraction problems quickly. The resource concludes with a strategy reflection prompt to encourage students to think critically about their problem-solving choices.