1. **State the problem:** Aurora baked some cookies. She gave 12 cookies to her family, sold $\frac{7}{9}$ of the cookies at a bake sale, and had 8 cookies left over. We need to find how many cookies she baked in total. 2. **Define variables:** Let $x$ be the total number of cookies Aurora baked. 3. **Write the equation:** She gave away 12 cookies, sold $\frac{7}{9}$ of the cookies, and had 8 left. The cookies sold and left over plus the 12 given away must equal the total: $$12 + \frac{7}{9}x + 8 = x$$ 4. **Simplify the equation:** Combine the constants on the left side: $$12 + 8 + \frac{7}{9}x = x$$ $$20 + \frac{7}{9}x = x$$ 5. **Isolate $x$:** Subtract $\frac{7}{9}x$ from both sides: $$20 + \cancel{\frac{7}{9}x} = x - \cancel{\frac{7}{9}x}$$ $$20 = x - \frac{7}{9}x$$ 6. **Simplify the right side:** $$x - \frac{7}{9}x = \frac{9}{9}x - \frac{7}{9}x = \frac{2}{9}x$$ So the equation becomes: $$20 = \frac{2}{9}x$$ 7. **Solve for $x$:** Multiply both sides by the reciprocal $\frac{9}{2}$: $$20 \times \frac{9}{2} = x$$ $$\cancel{20} \times \frac{9}{\cancel{2}} = x$$ $$10 \times 9 = x$$ $$90 = x$$ 8. **Answer:** Aurora baked $\boxed{90}$ cookies in total.