These are decimal numbers, and dots above some of the digits make them recurring decimals. One dot means the digit under it repeats infinitely. In other words, it goes on forever (and ever and ever).

Dot notation is used with recurring decimals. The dot above the number shows which numbers recur, for example \(0.5\dot{7}\) is equal to 0.5777777... and \(0.\dot{2}\dot{7}\) is equal to 0.27272727 ...