SI Unit
In 1960, the General Conference of Weights and Measures, the international authority on units, proposed a revised metric system called the International System of Units (abbreviated SI, from the French Système Internationale d’Unites). Table shows the seven SI base units. All other units of measurement can be derived from these base units.
SI Prefix
Like metric units, SI units are modified in decimal fashion by a series of prefixes, as shown in Table.
Roman Letters
Like Roman numerals represent a number system that was widely used throughout Europe as the standard writing system until the late middle ages. The ancient Romans explained that when a number reaches 10 it is not easy to count on one’s fingers. Modern Roman numerals use 7 letters to represent different numbers. These are I, V, X, L, C, D, and M which represent the numbers 1, 5, 10, 50, 100, 500, and 1000 respectively.
Greek Letters
Like The Greek alphabet has been used to write the Greek language since the late 9th or early 8th century BC.It is derived from the earlier Phoenician alphabet and was the earliest known alphabetic script to have distinct letters for vowels as well as consonants. In Archaic and early Classical times, the Greek alphabet existed in many local variants, but, by the end of the 4th century BC, the Euclidean alphabet, with 24 letters, ordered from alpha to omega, had become standard and it is this version that is still used for Greek writing today.
