Find the number less than 2, in FOL How to express that "the number less than 2 is odd" in first order logic, using only these symbols: 2, *, <, =, $\lnot$, $\land$, $\to$, $\exists$ and $\forall$ ?

By saying "the number less than 2" they are implicitly saying that there is exactly one number less than 2 (it's called a definite description). So, I would simply add this to the symbolization:

$$\exists x (x < 2 \land \forall y \ (y < 2 \rightarrow y = x) \land \
eg \exists z\ 2 \cdot z=x )$$