To simplify the expression \( \frac{x^{675}}{x^{453}} \), we can use the property of exponents which states that \( \frac{a^m}{a^n} = a^{m-n} \).
Applying this property here, we get:
\[ \frac{x^{675}}{x^{453}} = x^{675 - 453} \]
Now, we subtract the exponents:
\[ 675 - 453 = 222 \]
Thus, we have:
\[ \frac{x^{675}}{x^{453}} = x^{222} \]
So, the simplified form is:
\[ \boxed{x^{222}} \]