There are a total of twelve possible outcomes. This is because flipping a coin has two possible outcomes (either heads or tails) and rolling a number cube has 6 of them (1-6) so 2 times 6 is 12.
If you want to draw a tree diagram, first split your tree into two branches, one for heads and one for tails. Then, split both branches into 6 sub-branches each, so each branch has a full set of numbers from 1-6.
Or you can do it the other way around, first split your tree into 6 branches, then split all branches into 2 sub-branches each.
