This resource explores the concepts of sea level and elevation through a series of tasks that involve plotting elevations on a vertical number line, comparing heights and depths, and using inequality symbols to express relationships between signed numbers. Students will understand that sea level serves as a reference point, with positive values representing elevations above sea level and negative values below it. The document includes tasks that require students to analyze the relationships between various elevations, determine which is deeper or higher, and practice writing inequalities based on their observations. Through engaging with these exercises, learners will deepen their understanding of number lines, signed numbers, and the comparative relationships of numbers in terms of elevation.