This math topic focuses on measuring the length of lines drawn on a grid made up of 1x1 squares, and these problems involve irregular shapes with labeled line segments. The skill taught is an introductory concept to understanding perimeter, specifically practiced through finding the lengths of individual line segments in various figures presented on grids. Each problem requires calculating lengths of three distinct segments, potentially integrating counting along grid lines or using geometric principles to deduce distances. This topic helps students connect basic measuring skills with practical geometric and arithmetic applications.