In simple terms, the absolute value of a number is its "

distance" from the number

0.

With real numbers, this is quite simple, but when you have the
"2-dimensionality" of a complex number (represented as a + b*i*, where
*ii*=-1), you must use the pythagorean theorem to find
the hypotenuse, which is the distance from 0.

**|a + b***i*| = sqrt(aa + bb)