The expression "i=3" indicates that the variable i is assigned the value of 3. In programming and mathematics, variables are used to store data that can change or be manipulated. Here, i is simply a placeholder that now represents the number 3. In this context, i could be used in various calculations or functions. For example, if you were to use i in an equation, it would replace i with 3, allowing you to perform operations based on that value. This is a fundamental concept in both programming and algebra.