Can someon pls answer me this?!?! 10 PTS! I have been seeing a reoccuring number?

Hi all! i've been seeing the number 4 on my facebook notifications.. and on a few other things... and the other night i was playing monopoly, I, for some unknown reason kept rolling the number 4 copious amount of times. I don't know if this coincidental or what is it? what does it mean?