Job Outlook. Excellent. Respiratory therapists provide care and treatment for patients suffering from breathing and cardiopulmonary difficulties. They may also provide emergency medical care for patients who have experienced asphyxiation, heart attacks, or shock.
0 is a number alone or not. if you put 0 by itself its both a number and a digit.
A negative number is a number $x$ such that $x+y=0$ for some positive number $y$. In other words, a negative number is an object whose sum with some positive number equals the additive identity. A similar approach can be used to define other mathematical objects: $ 1 x=0$ is an object such that $a+x=a$. $ 2 x=\frac{1}{a}$ is an object such that $xa=1$.