To simplify the expression \( \frac{x^{675}}{x^{453}} \), you can use the properties of exponents. When dividing two expressions with the same base, you subtract the exponents:
\[ \frac{x^a}{x^b} = x^{a-b} \]
In this case:
\[ \frac{x^{675}}{x^{453}} = x^{675 - 453} = x^{222} \]
Therefore, the simplified expression is:
\[ \boxed{x^{222}} \]