Cardinal numbers

Question

Cardinal number for B ={x | x£N and 4< x < 10}

n(B) =

Answer 1

B = {x l x ε N and 4 < x < 10}

The cardinal number, n(B), for B is the number of elements of B.

N = set of natural numbers. So, B = {5, 6, 7, 8, 9}.

Therefore, n(B) = 5