Q:
# When do you use the union symbol in math?

**The union symbol in math, which looks like a capital U, is used when it is necessary to denote the collection of all the elements of two or more sets together.** The union of sets is one of the fundamental operations in set theory.

Credit:
D. Sharon Pruitt Pink Sherbet Photography
Moment
Getty Images

A set is a collection of defined or distinct objects. For instance, the numbers 1, 2 and 3 are distinct objects, but when they are combined, they form the set {1,2,3}. If this set is designated as set A, and set B is {2,3,4,5}, the union of set A and set B is set C, which is {1,2,3,4,5}. The equation of the union of set A and B is written AUB=C, or {1,2,3}U{2,3,4,5}={1,2,3,4,5}. This is expressed in words as A union B equals C,.

While the union of sets combines all the elements of both sets, the intersection of sets denotes only the elements the sets have in common. For instance, if set A is {1,2,3} and set B is {2,3,4,5}, then the intersection of sets A and B is {2,3}, as these are the only elements that appear in both sets. Intersection is written with a symbol like an upside down capital U, so if the intersection of sets A and B is set C, the equation would be written A?B=C, or {1,2,3}?{2,3,4,5}={2,3}.

Learn more about Algebra-
Q:
## What do kids learn in grade-two math?

A: Second grade mathematics covers mathematical topics such as fractions, addition and subtraction of two-digit numbers, and collection and presentation of da... Full Answer >Filed Under: -
Q:
## What is delta in math?

A: Delta refers to change in mathematical calculations. In some cases, this means a difference between two values, such as two points on a line. In other case... Full Answer >Filed Under: -
Q:
## What does "x|x" mean in math?

A: In math, "x|x" means "x, such that x" in set builder notation. It is used when building lists of numbers and defining domains when graphing. Full Answer >Filed Under: -
Q:
## What does "linear" mean in math?

A: When applied in mathematics, the term "linear" refers to any equation that, or any function whose equation is, a straight line. When placed on a graph, the... Full Answer >Filed Under: