This math topic focuses on calculating the length of lines on a grid composed of 1x1 squares. Presented in a format suitable for a perimeter introduction, it includes problems where participants need to measure line segments on irregular geometric shapes. The questions provide multiple labeled line segments on each grid-based image. Participants are required to determine and match the length of these irregular line segments accurately. This exercise serves as an introductory activity to understanding perimeter by practicing the measurement of lines in a visual and practical context.