Why does the commutative property of multiplication work?

Ammonia molecules have three hydrogen atoms and one nitrogen atom.how many of each atom arein five molecules of ammonia

The distance between two cities is 368 miles. if the scale on the map is 1/4 inch=23 miles, what is the distance between the cities on the map?

Two friends are reading books. jimmy reads a book with 21,356 words. his friend bob reads a book with one-and-a-half times as many words. which expression represents the number of words bob reads?