|≈||approximately equal to|
|digits||indicates that digits repeat infinitely (e.g. 8.294 369 corresponds to 8.294 369 369 369 369 …)|
Femtogram or femtogramme is equal to 10-15 gram (unit of mass), comes from a combination of the metric prefix femto (f) with the gram (g). Plural name is femtograms.
The kilogram or kilogramme (SI unit symbol: kg) is the base unit of mass in the International System of Units (SI) (the Metric system) and is defined as being equal to the mass of the International Prototype of the Kilogram (IPK, also known as "Le Grand K" or "Big K").