1. The question asks: "Where did the bottom h go?" This usually refers to a step in algebra or calculus where a term involving $h$ in the denominator disappears. 2. Typically, this happens in limits or difference quotients where $h$ is a small increment approaching zero. 3. For example, in the difference quotient for a derivative: $$\frac{f(x+h)-f(x)}{h}$$ 4. When simplifying, if $f(x+h)-f(x)$ contains a factor of $h$, it can be factored out: $$\frac{\cancel{h}(\text{some expression})}{\cancel{h}}$$ 5. The $h$ in numerator and denominator cancel, so the bottom $h$ "goes" away. 6. This cancellation is valid as long as $h \neq 0$. 7. After cancellation, you can safely take the limit as $h \to 0$. This is why the bottom $h$ disappears in such expressions.