What does a dot over a number mean?

A dot over a number means it is recurrent and will be the same infinitely. If it is a group between dots then those numbers will repeat in the same order in the same way as a single number

All that means is that a number repeats forever! The dot above the number shows which number will reoccur!

Dot over number means, this number is reoccurring, the number repeats itself, for example 1/3 .... can be written in decimal form as 0.3 but as 3 repeats itself the Three will have a dot over it.