2020: is it the first year or last year of the decade?

New Years Day I made a post on Facebook:

Chook wrote:
Happy New Year everyone and welcome to 2020, the last year of the decade.
What is it with our uneducated media that seem to think something that finishes with a 9 is the end of 10
$0.99 does not equal one dollar
At the end of the 9th lap in a 10 lap race you have not finished the race
Decade 1 was from 0001 to 0010
Nearing the end of the last millennium the media and pollies decided it sounded nicer to start a new millennium/decade on 00 instead of 01
Basic maths and just another reason the world has gone mad, if our pollies and media can't get something so basic correct it's no wonder that the world is on the state it's in

 
It created a bit of debate (as it was intended to do) as to who was right and who was wrong, the debate was quite civil with one person providing this link  to back up their opposing view.

https://www.timeanddate.com/calendar/decade.html?fbclid=IwAR2YqmavQXKETTqw9vp1lk-PdXI-OwRmSfPZZFtb8N2P4947_1dAV3OWB40

I finally got a chance to have a good read of the site this morning

Reading through and dissecting that information:
 
CE: Common Era begins with the year 1
(Therefore year 10 was the end of the 1^st decade, confirming using that system, years ending with 0 would be the end of decades, centuries and millennials)
 
AD: Anno Domini, or “year of the lord” signifying when Christians originally believed Christ was born. The Gregorian calendar refers to both BC and AD, AD began with the year 1
(Therefore year 10 was the end of the 1^st decade, confirming using that system, years ending with 0 would be the end of decades, centuries and millennials)
 
The article also goes onto state:
 

Avoid Confusion

A year listed without any letters is always Common Era, starting from year 1.
Adding CE or BCE after a year is only necessary if there is room for misunderstanding, e.g. in texts where years both before and after year 1 are mentioned.

 
My take on when the decades started and finished is further confirmed when you click on the link that the page you refer to has provided under “Calendar History”

7. Did the Millennium Start in 2000 or 2001?   


https://www.timeanddate.com/counters/mil2000.html


That link backed up my thoughts

The 21st Century Started in 2001

In 1999, the world was preparing for the New Year's party of a lifetime. The year number in the Gregorian calendar was about to tick over to 2000, supposedly ushering in not only the 21st century but also the 3rd millennium CE.
However, the party was held one year too early—it should have been on January 1, 2001.

Argue/debate away .................................

That'll confuse the hell out of the millennial bug then ..............no wonder our computers didn't stuff up at the start of 2000 LOL

The benchmark for starting or finishing any given thing requiring numerical calibration  is zero ,and the year 2020 to 2021 is the first part of  of that decade which when completed becomes 2021, 2022,2023 etc    . Going by the theory that  2021 or number one in any given situation is the start ,would mean that if for argument sake you were to reverse the order of counting as you would in say the launch of a rocket, it would be launched on one and not zero ( or blast off as they say in the movies ) , or if you were exploding an explosive device , you would have it going off at one instead of zero if one is the start of the numerical process and not zero ............bloody dangerous LOl. I suppose it's a bit like demerit points , you start with zero , and accumulate points ( or years ) as you go through the decade ( or points on your licence if you have a lead foot ) 
To put it another way , if your life was to be represented by a decade , you would start counting from the point of your birth ( point zero ) for your age to year one , two  etc. You wouldn't just not exist until you were one year old , and the first year of your life become part of your previous 9 months existence before your birth .
Oh ..........and a happy new year to you all .

Here are four examples that do not support each other

When you have been alive (a standalone item) for 6 months your age is stated as 6 months. At 12 months of age you celebrate your 1st birthday and you are regarded as a 1 year old. Therefore your time began at 0 years

On clocks, 1 o'clock is 1 hour after midnight (or noon) when  we refer to time within that hour as being from the previous day  1201 being 1 minute into the new day. I have heard this 1 hour period following midnight referred to as the zero hour.

Pages in books are typically numbered in descending roman numerals for the introductory pages and typically start at page 1 for the meaningful text. I have never seen a book with page number 0.

If you page number a computer generated document the first page default becomes page 1.

I have no idea what the above discussion means and therefore cannot draw any conclusions. I think I have just wasted 10-15 minutes of my day when I could have been doing something more meaningful.

I think your examples support that the years ending with 00, 10, 20 etc are the last year of the decade BanditDave

Chook wrote:I think your examples support that the years ending with 00, 10, 20 etc are the last year of the decade BanditDave

If you take Dave's clock example  for instance , the exact moment 2020 changed at midnight from 2019 that would become point zero . At any point after that we would be in 2020 , being the next stage of time i.e.  the next decade . you wouldnt have to wait a whole year to declare it a new decade

BanditDave wrote:On clocks, 1 o'clock is 1 hour after midnight (or noon) when  we refer to time within that hour as being from the previous day  1201 being 1 minute into the new day. I have heard this 1 hour period following midnight referred to as the zero hour.

that would come from 24 hour time rather than using am/pm

00:01hrs instead of 12:01 am

I think it's time for a nice cup of tea and a little lie down and let somebody on an enormous salary decide what is correct.

BanditDave wrote:I think it's time for a nice cup of tea and a little lie down and let somebody on an enormous salary decide what is correct.

Mate, they've got less idea than us Plebs