26794
12
456
_____
84394

If you only use whole numbers.

These decimals align neither left nor right

1345.19483
12.1
842

suppose it's just best.

Most everyday practical applications deal with numbers larger than one, and non-integers can usually be rounded to a consistent number of places after the decimal point. The arithmetic in people's ledgers is right-aligned. Now, if we were talking about a calculator that displays all numbers in scientific notation, that would be best left-aligned.