What is the common denominator of 8 7 5?

The common denominator of any two or more whole numbers, such as 8 7 and 5, will always be one (1) because 'common denominator' refers to the denominators of two or more fractions or mixed numbers, not whole numbers. So, a set of whole numbers (x,x) would have to be converted to their fraction equivalents, i.e., x/1, which will always yield a denominator of 1.