Before we attempt to solve, let's establish the fractions.
A coin has 2 sides; Heads and tails.
The chances of landing on either side is 1/2.
A standard number cube is numbered from 1-6. Since we're looking for the probability of an ODD number, let's count how many odds we have.
Odds in a standard number cube;
1, 3, 5.
3/6 (or 1/2 simplified) numbers on a standard number cube are odd.
So, since we're multiplying, let's find the product of our probabilities.
1/2 • 1/2 = 1/4.
Your probability is 1/4.
I hope this helps!