The probability that both number cubes have the number 4 facing up is 1/36
For a cube, we have the numbers 1,2,3,4,5 and 6
The number 4 only occurs once in the six
So, the probability of having the number 4 in a single roll is 1/6
Now, for two rolls, we have two probabilities which we will have to multiply
Thus, we have the probability as;