To multiply decimals by 10, 100, and 1000, use place value labels. Write the digits of the decimal using place value labels. Start with the first non-zero digit. To multiply by 10 move each digit one ...

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).

NPR's Scott Simon talks to math historian Glen Van Brummelen about his finding that the decimal point appeared in the 1440s, earlier than thought. How did the decimal point come to be? - the dot that ...