What are ordinal numbers used to indicate?

Ordinal numbers are specifically used to indicate the position of items in a sequence, which is why the correct answer is the option reflecting that concept. Ordinal numbers provide a way to rank or order items by establishing their place in a list, such as first, second, third, and so on. This is particularly important in early childhood education as children learn to understand sequences and the concept of ranking.

In contrast, the other options relate to different aspects of numerical understanding. For instance, numbers that indicate the number of items refer to cardinal numbers, while size comparisons would relate to measurement rather than ordering. Categories of items also do not involve sequencing but focus instead on grouping based on shared characteristics.