Let a and B Be Sets with Cardinal Numbers, N(A)= $n ( A \cup B ) = n ( A ) + n ( B ) - n ( A \cap B )$

question 142

True/False

Let A and B be sets with cardinal numbers, n(A)= a and n(B)= b, respectively. Decide whether the statement is true or false.
- $n ( A \cup B ) = n ( A ) + n ( B ) - n ( A \cap B )$