How many elements has P(A), if `A = phi`?

How many elements occur in nature ?

How many elements are present in 4th period?

How are elements classified ?

How are elements classified ?

If A and B are two sets such that A uu B has 20 elements, A has 8 elements and B has 16 elements, how many elements does A nn B have ?

How many elements are present in the each transition series?

How many elements are known till today ?

If S and T are two sets such that S has 21 elements, T has 32 elements, and S nn T has 11 elements, how many elements does S uu T have?

If X and Y are two sets such that X uu Y has 18 elements, X has 8 elements andY has 15 elements , how many elements does X nn Y have?