In throwing a die what is the probability of getting even or prime number

die number : 1 2 3 4 5 6

probability of getting even number : 3/6

because the number 2,4,6 are even number

the number 3 is 'how many even number?'

while 6 is the total number in throwing a die

probability of getting prime number : 2/6

because the number 3,5 are only prime number

the number 2 is 'how many prime number?'

while 6 is the total number in throwing a die

the question ask : getting even OR prime number

this means that we have to add the probability of even and prime number

3/6 + 2/6 = 5/6 (answer)

yes. we do proportions in probabilities.