From right to left the lifespan of numbers increases. Thus the mood each of them expresses.Nr. 3 is sad to have such a short life and taken away just after a year. Nr 4 is happy to be born, but his happiness will be short lived since he's going to be replaced in a year. Meanwhile Nr. 1 knows that soon after a few exchanges of numbers it's time will come as its life is only 10 y/long (thus the feels). Number 0 doesn't have to worry that much since his life span goes up to 100 and he has 86 more years to expire, but it is just a little bit startled realizing how fast years goes by, and before you know it its time will come as well. Meanwhile Nr. 2 is more relaxed than all of them. He will live 1000 years after all. But you can see the sadness of his face as he will witness the fall of many friends in the years to come, and he can't do anything because time always moves forward.
Here I explained this illustration for you fellas! (sad isn't it)
BUT.. on a happy note!
All these numbers will be reborn as tens, hundreds, thousands, millions, billions.... infinitely. They'll never die