People usually ask "What is the meaning of life?", Whereas the question should be "What are the meanings of life?". When I first started thinking about life in-depth, I created a meaning of my own and started believing that this particular meaning is the final meaning of life for everyone, while not realizing that the meaning I derived came through my experiences in life and not anyone else's. but now I have come to the conclusion that every life has a different meaning. My meaning of life would solely depend on my life experiences and circumstances and your meaning might be quite different because you went through different pains, sorrows, and hardships of life. life didn't treat you the way it treated me nor did it treat me the way it treated you, quite a tongue twister, isn't it? Well, life itself is a twister and now I am giving it a meaning of my own, but it might not be so twisting for someone else, it might be as simple as math and now I am telling you that math is easier for me but again, it might not be as simple for someone else "sighs".
Likewise, the meaning of life varies with age. it might revolve around the collection of baseball cards or Hot-wheel cars for a 13-year-old teenager but for someone in his/her 20's might always be thinking about his/her job and the amount of money he/she is going to earn in the future and the forces opposing him/her to achieve those dreams, but for someone who's married, the meaning could revolve around their bad marriage, or how his wife cheated on him or her husband doesn't give sufficient time to her. The point being made here is that with time your problems change and with that comes different meaning of life.
Doing a little math (as I previously said I am good at it), there are 7.7 billion people and they have an average life span of 79 years, that makes 608.1 billion, but let's round it off to have a better number, so there you are with 610 billion meanings of life.