For this problem, we are given a few statements and we need to determine which one expresses an equation.
An equation denotes equality, we need to find the statements that compare two situations saying they are equal.
The first statement is "A number m is greater than -10 but less than 21", notice how we don't have equality, but we have a range the statement talks about "less" or "greater", but doesn't talk about a definitive value. This is an inequation,
