1. **State the problem:** Simplify the expression $\frac{8520}{5} - 524 + 21$. 2. **Apply division first:** Calculate $\frac{8520}{5}$. $$\frac{8520}{5} = 1704$$ 3. **Substitute the result back:** $$1704 - 524 + 21$$ 4. **Perform subtraction:** $$1704 - 524 = 1180$$ 5. **Perform addition:** $$1180 + 21 = 1201$$ 6. **Final answer:** $$1201$$ The simplified value of the expression is 1201.