Understanding the domain and range is really important for learning how functions work. Here’s a simple breakdown:

1. Domain: This is all about what numbers you can use as inputs (or $x$-values) for a function. Knowing the domain helps you see what numbers are safe to put into the function without running into problems like division by zero or taking the square root of a negative number.

   For example, if you have the function $f(x) = \sqrt{x}$, the domain is $x \geq 0$. This means you can only use positive numbers or zero.

2. Range: This tells you what the possible outputs (or $y$-values) of a function can be. It helps you understand what results you can get from the function.

   For instance, with the function $g(x) = x^2$, the range is $y \geq 0$ because you can’t get a negative number when you square something.

In short, knowing the domain and range helps you understand how a function behaves. This makes it much easier to draw graphs and solve problems!