Textbook Problem

Let $X=\left\{1,2,3\right\},Y=\left\{1,2,3,4\right\}$ , and Z= $\left\{1,2\right\}$

1. Define a function $f:X\to Z$ that is onto but not one-to-one.
2. Define a function $g:X\to Z$ that is onto but not one-to-one.
3. Define a function $h:X\to X$ that is neither one-to-one nor onto.
4. Define a function $k:X\to X$ that is one-to-one and onto but is not the identity functions on X.