Glasby, S. P. Extended Euclid’s algorithm via backward recurrence relations. (English) Zbl 1011.11003 Math. Mag. 72, No. 3, 228-230 (1999). After using Euclid’s algorithm to find \((a,b)\) one can either work forward from the pair \(a,b\) or backwards from the pair \((a,b),0\) to find \(x,y\) such that \(ax+by= (a,b)\). The author claims that working backwards is better for calculation by hand, and also pedagogically, but that working forwards is better for use with a computer. Reviewer: H.J.Godwin (Egham) MSC: 11A05 Multiplicative structure; Euclidean algorithm; greatest common divisors PDFBibTeX XMLCite \textit{S. P. Glasby}, Math. Mag. 72, No. 3, 228--230 (1999; Zbl 1011.11003) Full Text: DOI