The letters of the Greek alphabet, Alpha, Beta, Gamma etc., etc. both upper and lower cases, were used to represent numbers
Numerals are symbols used to represent numbers.
Variables
Symbols used to represent unspecified numbers or values.
A written symbol that is used to represent speech; "the Greek alphabet has 24 characters".
A radix is the number of distinct symbols used to represent numbers in a particular base.
Variables (letters like x and y)
Numerals are different Numbers as for hieroglyphs are symbols used to represent numbers.
No. The Romans used letters to represent quantities. Whereas the Greeks used letters and symbols to represent quantities.
0 - 9 plus A - F
Operation symbols in mathematics are used to represent mathematical operations, such as addition (+), subtraction (-), multiplication (×), and division (÷). These symbols are used to perform calculations and denote relationships between numbers or variables.
An "R" with two vertical lines instead of just one
Chemical symbols are used to represent elements.