Problem
NT-B1-M07-P019 Inverse of \(7\)
#19
★★★☆☆ Level 3 of 5
Find the inverse of \(7\) modulo \(13\).
You may compute directly or use \(7^{11}\).
Direct computation: \(7\cdot2=14\equiv1\pmod{13}\). Hence the inverse of \(7\) is \(2\). This agrees with Fermat: \(7^{11}\) must also be an inverse of \(7\).
It is useful to show both viewpoints.