# Concept derivation guides

299 concept teaching guides, separate from the 36,000 individual question derivations.

[Search all questions & derivations →](/en/explore/)

1 1 results · Page 1 of 1



Concept guide



## [Two independent routes for Euler's criterion](/en/derivations/derivation-mko-euler-criterion-quadratic-residue-01/?from=%2Fen%2Fderivations%2F%3Fq%3Dmko-euler-criterion-quadratic-residue)

For p=7,a=-4 the Legendre value is -1 and a^3=6=-1 mod 7; 2 gives +1.

Euler criterion for quadratic residues

derivation-mko-euler-criterion-quadratic-residue-01





1 1 results · Page 1 of 1