A complex number is a cool idea in math. It has two main parts:

1. Real Part: This is the part we usually see every day. It’s a regular number, like $a$ in the complex number $a + bi$.

2. Imaginary Part: This part includes something called the imaginary unit $i$. This $i$ is special because it represents the square root of -1. It shows up as $b$ in $a + bi$.

So, when we write a complex number, we can express it like this:

$z = a + bi$

In this equation, $a$ is the real part and $b$ is the imaginary part. Both $a$ and $b$ can be any real numbers, which are the numbers we know, like 1, 2, or -3.

What makes complex numbers really interesting is that they help us solve problems that don’t have regular answers. For example, the equation $x^2 + 1 = 0$ can be tricky because there’s no regular number that works.

Once you start to understand how these parts fit together, using complex numbers can feel like discovering a whole new world in math!