U.S. told Russia that Crocus City Hall was possible target of attack (washingtonpost.com) More than two weeks before terrorists staged a bloody attack in the suburbs of Moscow, the U.S. government told Russian officials that Crocus City Hall, a popular concert venue, was a potential target, according to U.S. officials familiar with the matter.
Addition and multiplication are commutative in most number systems, and, in particular, between natural numbers, integers, rational numbers, real numbers and complex numbers.