No, you don't need a hyphen. It would be 10 decades or ten decades.
False
It means that it lasted that long.
1 decade = 10 years 10 decades = 100 years Today is 2010. 10 decades ago, it was 1910 .
10 decades in 1 century
Its 10. 10 decades = 1 century.
The goldrush lasted for several decades. Realistically, it could be said to extend from the first "official" gold strikes in 1851 through to the gold discoveries in Western Australia (Coolgardie and Kalgoorlie) in the 1890s.
Decade is a period of 10 years 103 divided by 10 = 10 decades
There are 10 decades in a century. Therefore, 3.5 centuries is equal to 3.5 x 10 = 35 decades.
70 decades are in 7 centuries. It's just 10 decades per century times 7 centuries (700 years).
10 Millennium = 1,000 Decade = 10 10 decades = 100 So 1,000 / 100 = 10
1 decade = 10 years 12 x 10 decades = 120 years