Simplify the following text for a Grade 6 native English-speaking person.
Original: More generally , we can call a subset of any ordinal cofinal in provided every ordinal less than is less than or equal to some ordinal in the set .
Simplified: The first , second , third , and fourth in this case are ordinal numbers . They result from the fact that the person has many objects , and they give them an order ( hence ` ordinal ' ) .