R stands for set real number set. A real number set is a set containing all rational numbers and irrational numbers, which is usually represented by the capital letter R. 1r, 1, q is a common subset of rational number sets, that is, a set of all rational numbers, which is represented by the bold letter Q, and R stands for set real number sets. A real number set is a set that contains all rational numbers and irrational numbers, and is usually represented by the capital letter R.

Common subset of r:

1, q, the set of rational numbers, that is, the ` set composed of all rational numbers, which is represented by the bold letter q. The rational number set is a subset of the real number set.

2, N+, positive integer set is the set of all positive integers and integers, and it is the set of natural numbers excluding 0 until infinity. Positive integer sets usually use symbols N+, N*, N 1, N >；; 0 means.

3, z, the set composed of all integers is called the integer set. It includes all positive integers, all negative integers and zeros. In mathematics, integer sets are usually represented by z.

According to avogadro's law, any gas contains the same number of molecules in the same volume at the same temperature and pressure, so R is a universal constant applicable to all gases. R=8.3 14J/(mol*K).