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).

Narrator: Fractions, Decimals and Percentages. Can you change one into another? Out of this crowd, can you find the ones that are the same value? It might look confusing, but ~ Det. Lewis Stinker: If ...

A usable fraction is a fraction you can use to measure with (i.e., 1/2, 1/4, 1/8, 1/16 inch). You measure with fractions of an inch. However, your calculator works in decimals of an inch. If you want ...