Chapter 5.5, Problem 2ES

Exercises 1-5 contains a while loop and a predicate. In each case show that if the predicate is true before entry to the loop, then it is also true exit from the loop.
2. loop: while $\left(m\ge 0\text{and}\text{m}\le \text{100}\right)$
   $\begin{array}{l}m:m+4\\ n:n-2\end{array}$
end while predicate: $m+n$ is odd