The "Correct" Way Of Specifying Calendar Dates

How do you express a number like "three hundred fifty two" using numerical digits instead of words? The arbitrarily established convention that we've adopted is to first write down the most significant digit (the one which represents the largest portion of the number, in this case the 3, since it represents "hundreds"), followed to the right by the next most significant digit (in this case the 5, since it represents "tens"), followed to the right by the least significant digit (in this case the 2, since it represents "ones"). Therefore the number would look like this:

352
(As an aside, the fact that we write the digits in this particular order is completely arbitrary. We could just have easily adopted some other convention, such as writing the same digits from right to left instead . And, had we chosen to write all of our numbers that way, then that convention would have been just as "correct" as the "left-to-right" method that we actually use. Of course 253 would then not indicate "two hundred fifty three.")

The left-to-right convention is also the way we express clock time. For example "four twenty seven and fifty one seconds" would be expressed by first writing the most significant portion (the hours), followed to the right by the next most significant portion (the minutes), followed to the right by the least significant portion (the seconds). Using colons to delimit each portion, the time would therefore be written as:

4:27:51
So then, why do so many of us (Americans, for example) express calendar time by writing the most significant portion (the year) in the right-most position? The correct (i.e., consistent) way to write a date would be to first write the most significant portion (the year), followed to the right by the next significant portion (the month), followed to the right by the least significant portion (the day). Therefore the correct way to express a date (for example, the date of the Apollo 11 lunar landing) would be:

1969 July 20
or, using only numbers, as:

1969/7/20
In fact, since clocks and calendars both indicate quantities of "time," the most consistent way of specifying time in general would be to combine those two separate concepts into one single concept. Any point in time could then be expressed in the single form:

year : month : day : hour : minute : second
where we would no longer require a separate delimiter (such as a "/") to be used only for the "date" portion.