Not way back, in an e-mail relayed by his father, a fourth-grade reader took concern with one in all my calculations in Math with Unhealthy Drawings:

half 3 – chapter 14 -hole-in-one prize insurance coverage pg. 169-170

12,500 to 1 payout chance and three,500 payout ratio is written. However after I calculate the payout ratio by doing 10,000/2.81 I bought roughly 3,558.7188 and after I spherical to the closest hundred I  bought 3,600 not 3,500. So, how did you get 3,500?

Please write again to clarify your pondering.

His forthright inquiry demanded a forthright reply. I wrote again:

What a superb query! Your calculations are right, and certainly, the result’s nearer to 3600 than 3500. So why did I write 3500?

My pondering is that 3500 feels like a “rougher” quantity than 3600.

To make sure, 3500 and 3600 each seem to have been rounded to the closest hundred. However in on a regular basis communication, we are likely to deal with 500 (being half of a thousand) as a rounder, coarser quantity. If somebody tells me a TV prices $3600, I count on it to be inside $50 of that worth. But when somebody tells me a TV prices $3500, I wouldn’t be stunned if the exact worth is, say, $3400, or $3675.

In on a regular basis use, $3600 means “rounded to the closest hundred,” whereas $3500 means one thing like “roughly midway between $3000 and $4000.”

So why did I decide the “rougher” quantity right here? As a result of the entire chapter is written with imprecise, rough-and-ready numbers. Particularly, the 12,500-to-1 chance is a crude estimate I grabbed from a web-based supply. I didn’t wish to put a really tough quantity (12,500) in juxtaposition with a extra exact quantity (3600). I needed the reader to be specializing in the gist of the argument, reasonably than the exact figures. Aggressive rounding strikes the main target away from the small print.

Besides, in fact, for very diligent and perceptive readers equivalent to your self, whose give attention to the small print can’t be budged!