Regular numbers can handle addition, subtraction, multiplication, and division. But what if you need to find the square root of a negative number (like \sqrt{-9})? Enter complex numbers! So, complex numbers are a bit like the more adventurous cousins of the real numbers we use every day. They include a real part and an imaginary part. The imaginary part has something to do with the square root of -1, which in real numbers doesn’t exist. So, a complex number looks like this: a + bi , where a is the real part and bi is the imaginary part.