Board Thread:General Discussion/@comment-1526346-20170916141829/@comment-31294034-20170917210008

Agent c wrote: So theres no confusion, I tend to go DD/MMM/YYYY - So 17/SEP/2017.

Putting the month first makes no sense at all. Americans do this because of the order of the largest maximum value.

$$Month = \{ 1, \ldots, 12 \}$$

$$Day = \{ 1, \ldots, 31 \}$$

$$Year = \{ 0, \ldots, \infty \}$$

With this definition we can see that the following is true and only true in this order.

$$\max Month < \max Day < \max Year $$

As such that

$$12 < 31 < \infty$$

TL;DR: We do it because 31 days is a larger number than 12 months and they are both smaller than infinite years. Thus we order them from least greatest maximum value to most greatest maximum value.