Mr Obama will give his third news briefing in as many days on Wednesday.
(from Article )

I have a hard time understanding the above sentence.

What is 'third news'? What does briefing refer to?

So, I don't understand what it means.

Could you please tell me?
News briefing = information provided to journalists/reporters about proposals and intentions.

Mr Obama will give his third briefing to journalists and reporters on Wednesday, having given his first on Monday and his second on Tuesday.
It shows a one-to-one correlation.

They made a quick start to what would eventually be a large family, having four children in as many years. They had 4 children in 4 consecutive years.

He can't keep a job. He's on his second job in as many months. In two months, he's had two jobs.

He gave his third press conference in as many days. He gave three press conference in three days.

It's reasonably common.
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Thanks, Feebs.
Got it.

The inserted part 'in as many days' is what I've not heard before, but is that common to indicate a situation like, as you said, 'having given his first on Monday and his second on Tuesday'?
 BarbaraPA's reply was promoted to an answer.
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Three days, three briefings.

The Red Sox have won five games in as many tries. They've tried to win five times and they've won five times.
Thanks, GG and Avangi.
I understand how the word 'as' works in your very understandable exapmles and the original sentence.