Adding 12 weeks, that is, 84 days, to August 14, 2011, gives November 6, 2011.
The 31st of January 2011.
Exactly 11 weeks after December 20, 2011 is March 6, 2012.
March 3 2011 is the date 11 weeks before May 19 2011.
In any given calendar year, the date five weeks after July 8 is August 17.
Subtracting 70 weeks from August 7, 2011 gives April 4, 2010.
August 1, 2011
Saturday the 7th of January 2012 is 8 weeks after Saturday the 12th of November 2011. Saturday the 17th of September 2011 is 8 weeks before it.
calendar date 13 weeks ago
Thursday the 19th of January 2012 is 12 weeks after it and the 4th of August 2011 was 12 weeks before it.
Monday the 23rd of April 2012.
From the date the question was asked, 27th of August 2012, 40 weeks before that would be the 21st of November 2011.
179 days after Sunday, August 29, 2010 = Thursday, February 24, 2011.