The expression "x - c" represents a simple mathematical operation where a constant value, represented by c, is subtracted from a variable, represented by x. In this context, x can take on different values, while c remains fixed. This operation is fundamental in algebra and is used to find the difference between the two quantities. In practical terms, if x represents a number of items and c represents a specific count of those items, then "x - c" calculates how many items are left after removing c. This concept is widely applicable in various fields, including finance, science, and everyday problem-solving.