Dog years: How do you calculate a dog's true age? Dog years: How do you calculate a dog's true age? Dog years: How do you calculate a dog's true age? Dog years: How do you calculate a dog's true age? BBC unique window BBC Dog years: How do you calculate a dog's true age? Dog years: How do you calculate a dog's true age? it first appeared in math textbooks Dog years: How do you calculate a dog's true age? How long will your dog live? http://www.bbc.co.uk/news/magazine-22458083