We have lower case and upper case letters. Why not lower and upper case numbers? John Weistroffer pointed this out to me while we were discussing why upper and lower letters exist. Then we figured that the numbers before the decimal point can be upper case, and the letters after it can be lower case. Thay way we don’t need to put the dot in there to indicate a decimal.
‘s kind of used that way in some old-tyme stores. The pre-decimal number is large, and in lieu of a decimal, the post-decimal numbers are half-size and placed upon a line. It’s akin to superscripting the “c” in a last name like “McAleer”.
believe it or not, when i was in the 4th grade i made the same query to my teacher, mrs. whybra. then i asked her ‘why a bra? why not a boustier?’
“oldstyle” numbers are somewhat upper and lower case. Well, anyway, some of the numbers have ascenders and some have decenders.
Lower-case numbers aren’t all that uncommon. The ‘Georgia’ font that a lot of web pages use uses lower-case numbers. Type ‘ABC1234567890abc’, and notice that the numbers match the lower-case letters’ size, not the capital letters. Also notice that the 3, 4, 5, 7, and 9 have descenders, just like some lower-case letters.