"X+Y" is a mathematical expression representing the addition of two variables, X and Y. In this context, X and Y can be any numbers or quantities. The result of this addition is called the sum, which is calculated by combining the values of X and Y. In practical applications, "X+Y" can represent various scenarios, such as combining resources, calculating totals, or solving equations. This simple operation is fundamental in mathematics and is used in various fields, including science, engineering, and finance, to analyze and interpret data effectively.