What does the K after a number mean?

Answer 1

Depending upon context it could mean:

• A temperature on the kelvin scale, eg 0K is absolute zero, 273.15K is the freezing point of water;
• the number is multiplied by 1000, eg 10K means 10 × 1,000 = 10,000 (this is the basis of the kilo- prefix in the metric system, written as a lower case 'k');
• an abbreviation for kilometres (especially with commentators), eg a 10K race is a 10 km race (this comes from the previous context in that 10K = 10,000 and metres is assumed to be/implicit as the length unit);
• in old computing terms it could refer to 1024 bytes, eg a Commodore Pet 3032 came with 32K RAM, meaning it had 32 × 1024 bytes = 32,768 bytes of RAM (1024 is the closest power of 2 to 1000, and the "bytes" was implicit when talking about memory sizes back then).