>>30 claimed that a mathematical equation containing numerical digits should be solved with something that lies in the number line. By "number" I suppose he means the reals.
Then you have the line of integer numbers. There are many integer equations and functions which do not return an integer, but something outside the line of integers. For example, x = 1 / 2. 1 and 2 are from the integers line, x is not.
So if it happens with integer operations which return reals, why can't we have a line of reals for which some operations return strings such as "nullity", or hyperreals?