Consider a random experiment of rolling a fair die. The probability of getting an odd number or a number less than 4 is ______ (Rounded off to two decimal places).
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List or count the die faces that are odd, less than 4, or both, and use the addition rule of probability to avoid double counting.
Step 1: List every outcome of the die. $S = \{1, 2, 3, 4, 5, 6\}$, each with probability $1/6$. Step 2: Directly identify the outcomes that satisfy odd OR less than 4. An outcome counts if it is odd, or less than 4, or both. Checking each face: 1 (odd and less than 4, counts), 2 (less than 4, counts), 3 (odd and less than 4, counts), 4 (neither, does not count), 5 (odd, counts), 6 (neither, does not count). The favorable outcomes are $\{1, 2, 3, 5\}$. Step 3: Count and divide. There are 4 favorable outcomes out of 6 equally likely outcomes, so \[ P = \frac{4}{6} = \frac{2}{3} \approx 0.67 \] \[ \boxed{P \approx 0.67} \]
