300000000 years equals three hundred million years
earth is over_400_million_years_old. century is years. one_unit_of_time is century. century is 100_years. millisecond is one_thousandth_of_second. millenium is 1000_years. earth is 4.5_billion_years_old. decade is 10_years. 1530s is decade. hundred_years is century.