Original: Twelve dozen ( 122 = 144 , the duodecimal 100 ) are known as a gross ; and twelve gross ( 123 = 1,728 , the duodecimal 1,000 ) are called a great gross , a term most often used when shipping or buying items in bulk .
Simplified: 12 dozen ( 144 items ) are a gross , 12 gross ( 1728 items ) are called great gross .