Here’s a clean, factual draft you can use depending on where you’ll post it (e.g., search result, FAQ, article, or voice response): The Big Bang Theory has 12 series (seasons).
There are 12 series of The Big Bang Theory . how many series of big bang theory
The show aired 12 series in total, from September 24, 2007, to May 16, 2019. Here’s a clean, factual draft you can use