The expression "i=1" is a simple assignment statement commonly used in programming and mathematics. In this context, "i" is a variable that is being assigned the value of 1. This means that wherever "i" is referenced later in the code or equation, it will represent the number 1. In programming, variables like "i" are often used in loops or calculations. For example, in a loop, "i" might serve as a counter to track how many times a certain action has been performed. This is particularly common in languages such as Python, Java, and C++.