The expression "2 + 9" represents a simple addition problem in mathematics. In this case, the number 2 is combined with the number 9 to find the total. Addition is one of the basic arithmetic operations used to calculate the sum of two or more numbers. When you add 2 and 9, you count up from 2 by 9 units. This results in a total of 11. Therefore, the answer to the equation "2 + 9" is 11, which can be used in various real-life situations, such as counting objects or measuring quantities.