Qur'an talks of Prophet Noah's age in 29:14 as follows.

And We certainly sent Noah to his people, and he remained among them a thousand years minus fifty years, and the flood seized them while they were wrongdoers.

Why does it say thousand years minus fifty years rather than directly saying 950 years? More precisely, what I'd like to ask is how should we understand this verse ? Does it literally mean Prophet Noah lived for 950 years or might it have a figurative meaning?