We first need a table that lists all outcomes. The table is shown below.
The outcome that is a multiple of 6 are 6 and 12 and there are six outcomes out of 36 total outcomes
The outcome that is a multiple of 4 are 4, 8, and 12 and there are nine out of 36 total outcomes
There are a total of 9+6=15 outcomes of multiple of 6 OR multiple of 4, so the probability is 15/36 which simplified to 5/9
The outcome that is a multiple of 6 are 6 and 12 and there are six outcomes out of 36 total outcomes
The outcome that is a multiple of 4 are 4, 8, and 12 and there are nine out of 36 total outcomes
There are a total of 9+6=15 outcomes of multiple of 6 OR multiple of 4, so the probability is 15/36 which simplified to 5/9