Answer:
m + 1
Step-by-step explanation:
Given set,
B = {∅, {1}, {1, 2}, {1, 2,3}, · · · , {1, 2, · · · , m}},
Since, the elements of S are,
{} , {1}, {1, 2}, {1, 2, 3}....... {1, 2,.....m }
Thus, every next set contains one more succeeding natural number than the previous set.
So, if the last set contains m natural numbers.
Then there are 'm + 1' sets in B ( m sets included ∅ )
Hence, the number of elements in B is 'm+1'
I.e. Cardinality of B is m + 1.
