This learning resource focuses on mastering the concept of elapsed time. The primary objective for students is to calculate elapsed time using number lines and analog clock models to tackle one-step word problems regarding time intervals. Effective strategies including visual aids like number lines and analog clocks are provided to help students understand how to measure time. Examples are given, such as moving from 2:10 to 2:45 on a number line and counting minutes on an analog clock. Guided practice tasks encourage students to apply their understanding by calculating elapsed time in various scenarios, while independent practice allows for further reinforcement of the concept. A challenge task prompts critical thinking by asking students to determine end times based on a given duration. The resource also includes a self-check for confidence in solving elapsed time problems.