The 21st century is 2001-2100 because we count them and the first century was 1-100 (there is no 0AD). But nobody refers to decades as the nth decade. We in fa

The 21st century is 2001-2100 because we count them and the first century was 1-100 (there is no 0AD). But nobody refers to decades as the nth decade. We in fact refer to them by their leading digit. So no, it’s the 20s again.