Choice Choice B is the correct answer. This is a special case demonstrating the additive identity.

1. Start with the equation: $x + 18 = 18$
2. Subtract 18 from both sides: $x = 18 - 18$
3. Simplify: $x = 0$
4. Verify: $0 + 18 = 18$ ✓

When we add zero to any number, the number remains unchanged. This is the additive identity property.

💡 Zero Matters: Never assume zero can't be a solution! It's a perfectly valid answer that appears frequently in mathematics.

Choice Choice D is incorrect because this results from adding instead of subtracting: $18 + 18 = 36$. This is the wrong operation.

Choice Choice A is incorrect because this confuses the constant (18) with the solution. Seeing 18 on both sides doesn't mean $x = 18$.

Choice Choice B is incorrect because this might come from thinking "the same numbers divide to 1," but division isn't how we solve addition equations.