Fill in the blank proofs for Section 2.1

1. Claim: If n and m are odd, then m + n is odd.
   Proof. Click here.
   
2. Claim: If n is even, then n² is even.
   Proof. Click here.
   
3. Claim: If n is odd, then n² - 1 is divisible by 4.
   Proof. Click here.