Original: Nicomachus ( ) ( c. 60 c. 120 ) was an important mathematician in the ancient world and is best known for his works Introduction to Arithmetic ( Arithmetike eisagoge ) and The Manual of Harmonics in Greek .
Simplified: He was strongly influenced by Aristotle and is best known for his works Introduction to Arithmetic ( Arithmetike eisagoge ) and The Manual of Harmonics in Greek .