What type of numbers is the teacher using when assigning students in line as "First, second, third, fourth"?

The teacher is using ordinal numbers when assigning students in line as "First, second, third, fourth." Ordinal numbers indicate the position or order of items in a sequence. They are utilized to rank or order objects, people, or concepts based on their place in a specific arrangement. In this case, terms like "first," "second," and "third" clearly illustrate the ranking of students in line rather than indicating quantity or representing individual categories.

In contrast, nominal numbers would categorize students without implying any order, while cardinal numbers represent a count of items, such as how many students there are. Real numbers encompass all the rational and irrational numbers but are not relevant in the context of ranking or ordering students. Therefore, the use of "first," "second," and "third" unambiguously demonstrates that ordinal numbers are the correct terms being employed in this scenario.