What is the common denominator of 7 and 10?

The common denominator of any two or more whole numbers, such as 10 and 15, 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.