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).

Watch this video from Maths and Numeracy which shows how Snoot, Fin and Plimble compare fractions, decimals and percentages when fuelling their saucer. Narrator:I see. Your drum of nitroplasm holds ...