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).

Review of representation of natural number, integers, rational numbers on the number line. Representation of terminating/non-terminating recurring decimals, on the ...

THIS is a comprehensive text-book clearly written and well arranged. There is a useful chapter on abridged methods and approximations, and a note (in the appendix) on the metric system. Compound ...