We would all start speaking math.
Twelve is twelve, PERIOD
Math uses letters to indicate that specific numbers are not known or as an abbreviation for certain constant.
Satan put letters in math during the time period in which the emancipation proclamation was being signed
dozen
Oh, dude, you write Twelve Million Twelve Thousand Twelve as 12,012,012. Easy peasy lemon squeezy. Like, just throw in some commas every three digits starting from the right, and you're good to go. Math and stuff, you know?
In ordinary everyday letters . . . pi In Greek letters . . . Π
Trig
Variables
24
Letters used in math are called variables.
Arithmetic