What were some of Leonardo's Fibonacci's accomplishments in math?

Leonardo of Pisa, known as Fibonacci, is best known for introducing the Fibonacci sequence to the Western world through his book "Liber Abaci" published in 1202. This sequence, where each number is the sum of the two preceding ones, has significant applications in mathematics, nature, and art. Fibonacci also contributed to number theory and introduced the Hindu-Arabic numeral system to Europe, which replaced the Roman numeral system and revolutionized arithmetic. His work laid the foundation for modern mathematics and influenced various fields, including computer science and economics.