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).

Know that you know your whole numbers (整数, zhěng shù) in Chinese, you can talk about rational numbers (有理数，yǒu lǐ shù) in decimals (小数, xiǎo shù), fractions (分数, fēn shù), and percents (百分数, bǎi fēn ...