Chapter P - Section P.1 - Algebraic Expressions, Mathematical Models, and Real Numbers - Exercise Set - Page 19: 142

A real number can not be both rational and irrational. By the simple definition of an irrational number being a real number that isn't rational, we can tell that a real number can't be both rational and irrational.

A real number can not be both rational and irrational. By the simple definition of an irrational number being a real number that isn't rational, we can tell that a real number can't be both rational and irrational.