20 is definitely a number, an integer. 2/3 of voting members is not an integer; it is a differential equation, as in calculus. It is an expression of the relationship of variables, it explains x as a function of y. As the number of people rises or increases (at the meeting) the equation explains how the other variable changes in relation. I would argue, then, that both expressions are not numbers. In fact, whether or not "2/3 of the voting members" is a hard number is exactly the question at hand (does it mean 2/3 of the membership roll of 80 or does it mean 2/3 of whatever number of people we count in the seats at a given time?), so claiming it's a hard number is begging the question. (I mean that in the sense I learned in philosophy, i.e. stating positively the question at hand as a premise, not in its current common usage as a substitute for "raising" the question.) I am enjoying this discussion of what should be a really simple concept. My church has a similarly vague definition of quorum I'd love to amend.