He studied astronomy and mathematics from works of Levi бен Gershom and Al-Battani. In 1365, he published the astronomical tables «Six wings» (Hebrew: שש כנפים), including, besides common astronomical information, the data for the Jewish calendar calculations (which were used up to 17th century).
Bonfils was the first European mathematician who has published (in the treatise «Way to division», Hebrew: דרך חילוק) the general theory of decimal fractions. However before works of Simon Stevin this theory hasn't received distribution. He had translated a number of books from Latin to Hebrew. Some his works had been translated to Latin and (in Byzantium) to Greek.
- Wings of Eagle, Hebrew: שש כנפים, in six books. Other name: Six wings, Hebrew: שש כנפים. The main astronomical work of Bonfils.
- Way to division, Hebrew: דרך חילוק — a course of decimal arithmetics, including decimal fractions.
- Gandz, S.: The invention of the decimal fractions and the application of the exponential calculus by Immanuel Bonfils of Tarascon (c. 1350), Isis 25 (1936), 16–45.
- P. Solon: The Six Wings of J. Bonfils and Michael Chrysokokkes, in: Centaurus, 15 (1970) 1–20