Evaluate: $64^2-36^2$
To solve this problem, I could use the difference of squares formula: $a^2-b^2=(a+b)(a-b)$. In this case, $a=64$ and $b=36$, so I can rewrite the expression as $(64+36)(64-36)$. This simplifies to $100\cdot 28$, which is much easier to calculate. Multiplying by 100 just means adding two zeros to the end of the number, so $100\cdot 28=2800$.

