No. A decade is ten years. So 10 decades is 100 years. Here's a useful guide I cooked up earlier: Decade = 10 years Century = 100 years Millenium = 1000 years
43 years
1970, starting this year (2010).
1 decade is 10 years. The date is 10/27/11, so 10/27/01
in one decade there are 10 years, so if you times 10 by 4 you will get 40 so there are 40 years in 4 decades.