1. Let's start by defining the terms. 2. The **domain** of a function is the set of all possible input values (usually $x$ values) for which the function is defined. 3. The **range** of a function is the set of all possible output values (usually $y$ values) that the function can produce. 4. In simpler terms, the domain answers the question: "What can I put into the function?" while the range answers: "What can I get out of the function?" 5. For example, if you have the function $f(x) = \sqrt{x}$, the domain is all $x \geq 0$ because you cannot take the square root of a negative number in the real numbers. 6. The range of this function is also all $y \geq 0$ because square roots are always non-negative. 7. Remember, domain relates to inputs, range relates to outputs.