Why was Fibonacci's Liber abaci important in the spread of Hindu-Arabic numerals in Europe?

Fibonacci’s Liber abaci (1202) was pivotal in the spread of Hindu-Arabic numerals throughout Europe because it served as the first comprehensive European work to introduce and explain these symbols to a broad audience.12

While the numerals were previously known to a limited number of intellectuals through Latin translations of works by mathematicians like al-Khwārizmī, Fibonacci’s book provided a practical framework for their use. The first seven chapters of Liber abaci clearly explained the principle of place value and demonstrated how to perform arithmetical operations using the new system.32

Crucially, Fibonacci applied these techniques to real-world commercial problems—such as profit margins, interest calculations, and currency conversion—which resonated with the rising class of Italian merchants. The book was widely copied and imitated, leading to the establishment of schools where maestri d’abbaco (abacus masters) taught the "new math" to the sons of merchants. This practical application in trade and finance was essential in transitioning European society away from traditional methods, such as the abacus and Roman numerals, toward the modern decimal system.42315