A numeral system (or system of numeration) is a writing system for expressing numbers, that is, a mathematical notation for representing numbers of a given set, using digits or other symbols in a consistent manner. It can be seen as the context that allows the symbols "11" to be interpreted as the binary symbol for three, the decimal symbol for eleven, or a symbol for other numbers in different bases.
Ideally, a numeral system will:
Roman numerals, the numeric system used in ancient Rome, employs combinations of letters from the Latin alphabet to signify values. The numbers 1 to 10 can be expressed in Roman numerals as follows:
The Roman numeral system is a cousin of Etruscan numerals. Use of Roman numerals continued after the decline of the Roman Empire. From the 14th century on, Roman numerals began to be replaced in most contexts by more convenient Hindu-Arabic numerals; however this process was gradual, and the use of Roman numerals in some minor applications continues to this day.
In music, Roman numeral analysis involves the use of Roman numerals to represent chords. In this context, Roman numerals (I, II, III, IV, ...) typically denote scale degrees (first, second, third, fourth, ...). When a Roman numeral is used to represent a chord, it is meant to indicate the scale degree corresponding to its root note, which is the note on which the chord is built. For instance, III is the Roman numeral which denotes either the third degree of a scale, or the chord built on that degree. In many cases, uppercase Roman numerals (such as I, IV, V) represent major chords while lowercase Roman numerals (such as i, iv, v) represent the minor chords (see Major and Minor below for alternative notations); elsewhere, upper-case Roman numerals are used for all chords.
In the most common day-to-day use, Roman numerals allow musicians to quickly understand the progression of chords in a piece. For instance, the standard twelve bar blues progression is denoted by the roman numerals I7 (first), IV7 (fourth), and V7 (fifth). In the key of C (where the notes of the scale are C, D, E, F, G, A, B), the first scale degree (Tonic) is C, the fourth (Subdominant) is F, and the fifth (Dominant) is a G. So the I7, IV7, and V7 chords are C7, F7, and G7. Similarly, if one were to play the same progression in the key of A (A, B, C♯, D, E, F♯, G♯) the I7, IV7, and V7 chords would be A7, D7, and E7. In essence, Roman numerals provide a way to abstract chord progressions, by making them independent of the selected key. This allows chord progressions to be easily transposed to any key.
Chuvash numerals is an ancient numeral system the Chuvash people used. (Modern Chuvash use Hindu-Arabic numerals.)
Those numerals originate from finger numeration. They look like Roman numerals, but larger numerals stay at the right side. It was possible to carve those numerals on wood. In some cases numerals were preserved until the beginning of 20th century.
The term crime does not, in modern times, have any simple and universally accepted definition, but one definition is that a crime, also called an offence or a criminal offence, is an act harmful not only to some individual, but also to the community or the state (a public wrong). Such acts are forbidden and punishable by law.