Fill in the blank to make the following a true statement:
$U^{\prime} \cap A = \ldots$

The number of subsets of $\{1, 2, 3, \ldots, 9\}$ containing at least one odd number is

Taking the set of natural numbers as the universal set,write down the complement of the following set:
$A = \{ x : x \text{ is a perfect square} \}$

Fill in the blank to make the following statement true: $\varnothing^{\prime} \cap A = \text{?}$

Let $U = \{1, 2, 3, 4, 5, 6, 7, 8, 9, 10\}$,$A = \{1, 2, 5\}$,and $B = \{6, 7\}$. Find $A \cap B'$.

Taking the set of natural numbers as the universal set,write down the complement of the following set:
$A = \{ x : x \text{ is an odd natural number} \}$