1. The problem is to understand the expression $0.15 \pm 0.2$ which represents a value with an uncertainty or tolerance. 2. The notation $a \pm b$ means the value can range from $a - b$ to $a + b$. 3. Here, $a = 0.15$ and $b = 0.2$. 4. Calculate the lower bound: $$0.15 - 0.2 = -0.05$$ 5. Calculate the upper bound: $$0.15 + 0.2 = 0.35$$ 6. Therefore, the value lies in the interval $$[-0.05, 0.35]$$. This means the value could be as low as $-0.05$ or as high as $0.35$, representing uncertainty or error margin around $0.15$.