1. The problem states: "A number decreased by 7 is at most 13." We need to write an inequality for this. 2. Let the number be $x$. "Decreased by 7" means $x - 7$. 3. "At most 13" means less than or equal to 13, so the inequality is: $$x - 7 \leq 13$$ 4. To solve for $x$, add 7 to both sides: $$x - 7 + 7 \leq 13 + 7$$ $$\cancel{x} \leq 20$$ 5. So the solution is: $$x \leq 20$$ This means the number can be any value less than or equal to 20. Final answer: $x \leq 20$