This topic involves learning to define the domain and range of functions by interpreting number lines and expressing the information as inequalities. The problems require identifying whether a given range or domain, marked on a number line, should be described using inequalities that include or exclude endpoints (using "<" vs. "≤" or ">" vs. "≥"). Students must analyze the graphical representation of domains and ranges and choose the correct form of inequality to describe them accurately. There are multiple-choice questions for each scenario to help understand these concepts without involving unions of intervals.