Step-by-step explanation:

Here are some of the more commonly used variables:

n often represents some unknown quantity or number — probably because n is the first letter in number.

x is often the variable you solve for, maybe because it’s a letter of mystery. The letter x also is used to indicate multiplication (×). You have to be clear when you use an x, that you dont mean multiply.

C and k are two of the more popular letters used for representing known amounts or constants. The letter C is used frequently in calculus and physics, and it’s capitalized in those cases — probably due to tradition.

The letters that represent variables and numbers are

usually lowercase: a, b, c, and so on. Capitalized letters are used most commonly to represent the answer in a formula; for example, the capital A for area of a circle equals pi times the radius squared, A = πr2.