Which set is the subset of all given sets?

Write the set builder form of the set $ A = \{-1, 1\} $.

If $A = \{1, 2, 3, \ldots, 10\}$,then the number of non-empty subsets of $A$ containing only odd numbers is

The set $A = \{ x : x \in \mathbb{R}, x^2 = 16 \text{ and } 2x = 6 \}$ is equal to

Write the following set in the set-builder form: $\{ 5, 25, 125, 625 \}$

Consider the sets $\phi, A=\{1,3\}, B=\{1,5,9\}, C=\{1,3,5,7,9\}$. Insert the symbol $\subset$ or $\not\subset$ between the pair of sets: $A, \ldots B$.