The expression "(1 - r)" represents a mathematical operation where "r" is subtracted from 1. This formula is commonly used in various fields, including finance and statistics. For example, if "r" represents a rate of return or a probability, then "(1 - r)" can indicate the remaining portion or the complement of that value. In finance, if "r" is the interest rate, then "(1 - r)" shows the fraction of the principal that is not earned as interest. Similarly, in probability, if "r" is the likelihood of an event occurring, then "(1 - r)" represents the chance of that event not happening, providing a complete view of possible outcomes.