Probability for either side of a fair coin: 1/2. A coin has two sides.
Probability of any side of a dice: 1/6. A cube has 6 sides.
P(number rolled on dice is less than 3: 1/6+ 1/6 = 2/6 = 1/3.
Why do we add 1/6 two times? On a cube there are 2 numbers less than 3. You know the numbers to be 1 and 2.
P(Coin is heads): 1/2
P(Coin is heads AND dice is less than 3): 1/3 x 1/2 = 1/6.
Understand?
