1. **State the problem:** Solve the equation $-4 = h - 20$ for $h$. 2. **Formula and rules:** To isolate $h$, add 20 to both sides of the equation to cancel out the $-20$ on the right side. 3. **Intermediate work:** $$-4 = h - 20$$ Add 20 to both sides: $$-4 + 20 = h - 20 + 20$$ $$16 = h + \cancel{-20} + \cancel{20}$$ 4. **Solution:** $$h = 16$$ 5. **Explanation:** We added 20 to both sides to keep the equation balanced and isolate $h$. The $-20$ and $+20$ cancel each other out, leaving $h$ alone on the right side. The left side simplifies to $16$, so $h = 16$.