1. **State the problem:** Find the difference between the highest and lowest values in the list: $-4.3, -1.54, -6.819, -9.04, -12.3, -11$. 2. **Identify the highest and lowest values:** - Highest value is the maximum number in the list. - Lowest value is the minimum number in the list. 3. **Find the highest value:** Among the numbers, $-1.54$ is the greatest because it is closest to zero. 4. **Find the lowest value:** Among the numbers, $-12.3$ is the smallest because it is the farthest from zero in the negative direction. 5. **Calculate the difference:** $$\text{Difference} = \text{Highest} - \text{Lowest} = -1.54 - (-12.3)$$ 6. **Simplify the subtraction:** $$-1.54 - (-12.3) = -1.54 + 12.3$$ 7. **Perform the addition:** $$-1.54 + 12.3 = 10.76$$ **Final answer:** The difference between the highest and lowest values is $10.76$.