The P(even or divisor of 28) = P(even) + P(divisor of 28) - P(even and divisor of 28). The P(even) = 2/4 = 1/2. The P(divisor of 28) = 2/4 = 1/2. The P(even and divisor of 28) = 2/4 = 1/2 as 2,4 are even numbers and divisors of 28.
In the fraction Jonah made split his table into 10 parts to show 3/5 and to get the 10 parts he multiplied 5 by 2 to get 10 and you have to do the same to the 3 so 3 multiplied by 2 is 6