Question: how many ipads are there?
Answer: There have been a total of 21 iPad models over the years, which we can divide into four sub-brands: iPad, iPad 2, iPad 3, iPad 4, iPad 9.7in (2017), iPad 9.7in (2018), iPad 10.2in (2019) iPad Air, iPad Air 2, iPad Air (2019) iPad mini, iPad mini 2 with Retina display, iPad mini 3, iPad mini 4, iPad mini (2019)