3.10 Legendre and Jacobi Symbols

• This section was kind of confusing when it talked about the different rules for the Legendre symbol. I was confused on how if (a/n)=+1 a could be a square mod n. It took me a second to realize that if n is composite then a doesn't have to be a square of the primes and therefore (a/n)=+1 doesn't necessarily mean that a is a square mod n. Only if n is a prime.
• I thought it was interesting however to find easier ways to find if a is a square mod n.