In mathematics, the lowest common denominator or least common denominator (abbreviated LCD) is the least common multiple of the denominators of a set of vulgar fractions. For instance, the LCD of {1/2, 1/4} is 4, while the LCD of {1/2, 1/3} is 6. Mathematics, often abbreviated maths in Commonwealth English and math in American English, is the study of abstraction. ... In arithmetic and number theory the least common multiple or lowest common multiple (lcm) or smallest common multiple of two integers a and b is the smallest positive integer that is a multiple of both a and b. ... In algebra, a vulgar fraction consists of one integer divided by a non-zero integer. ... In algebra, a vulgar fraction consists of one integer divided by a non-zero integer. ...

By using this (or any multiple of it) as a denominator, it enables addition, subtraction or comparison of fractions: Addition is one of the basic operations of arithmetic. ... In mathematics, subtraction is one of the four basic arithmetic operations. ...

• 1/2 + 1/4 = 2/4 + 1/4 = 3/4;
• 1/2 − 1/3 = 3/6 − 2/6 = 1/6;
• 1/3 < 2/5 since 5/15 < 6/15.

In non-mathematical use, the term is used figuratively to refer to the "lowest"—least useful, least advanced, or similar—member of a class or set which is common to things that relate to members of that class. For instance, ASCII characters are the lowest common denominator for computers, in that this set is very limited, but practically every modern computer can interpret binary data into these characters. There are 95 printable ASCII characters, numbered 32 to 126. ... The tower of a personal computer (specifically a Power Mac G5). ...

In the context of mass media, the term is commonly used to refer to a target audience. The implication is that the media in question are targeted at the lowest expectations of an audience with a varying range of tastes. In this regard, it is often also used to mean "dumbest people", or those whose tastes match the lowest values of the wider audience. Action movies and most television programming are often considered to be targeted at the lowest common denominator of the population. It is also used to describe negotiations and agreements which only cover the points where everybody's previous positions coincide. Highest common factor may be a more accurate description, but would not have the same negative sound. Mass media is the term used to denote, as a class, that section of the media specifically conceived and designed to reach a very large audience (typically at least as large as the whole population of a nation state). ... Movie poster for Die Another Day, the 20th James Bond movie. ... In mathematics, the greatest common divisor (gcd), sometimes known as the greatest common factor (GCF) or highest common factor (hcf) of two integers which are not both zero is the largest integer that divides both numbers. ...