1. **State the problem:** Evaluate the expression $\left(12 + \frac{3}{5}\right) \times 0.45$. 2. **Write the expression clearly:** $$\left(12 + \frac{3}{5}\right) \times 0.45$$ 3. **Convert the mixed expression inside the parentheses to a single fraction or decimal:** $$12 + \frac{3}{5} = 12 + 0.6 = 12.6$$ 4. **Multiply the result by 0.45:** $$12.6 \times 0.45$$ 5. **Calculate the multiplication:** $$12.6 \times 0.45 = 5.67$$ 6. **Final answer:** $$\boxed{5.67}$$