Two number cubes are rolled. each number cube has sides numbered 1 through 6. what is the probability that the outcome of the roll is an odd sum or a sum that is a multiple of 5?

There are a total of 6*6=36 outcomes (sums), of which 18 are odd, 18 are even, so the probability of getting an odd sum is 18/36
of the 36 outcomes, there are four fives and three tens, so the probability of getting a multiple of 5 is 7/36
but the four fives are also odd numbers, so we need to subtract 4/36
the result is: 18/36 +7/26 -4/36=21/36=7/12 =0.58333333

to see the total outcomes, Google image "two number cubes sum" or go to this website:
https://www.eduplace.com/math/mw/background/5/06b/te_5_06b_probability_devel.html