Understanding Uninitialized Variables

When JavaScript variables are declared, they have an initial value of undefined. If you do a mathematical operation on an undefined variable your result will be NaN which means "Not a Number". If you concatenate a string with an undefined variable, you will get a literal string of "undefined".


Initialize the three variables a, b, and c with 5, 10, and "I am a" respectively so that they will not be undefined.