The Roman numeral "DCCLXX" represents the number 770. In this numeral, "D" stands for 500, "CC" represents 200 (100 each), "L" is 50, and "XX" equals 20 (10 each). When you add these values together, you get 500 + 200 + 50 + 20 = 770. Roman numerals are a numeral system originating from ancient Rome. They use combinations of letters from the Latin alphabet, specifically I, V, X, L, C, D, and M. This system was widely used throughout the Roman Empire and is still seen today in various contexts, such as clock faces and book chapters.