Answer:
When rolling two number cubes, the possible outcomes of the sum of the numbers on the top faces are from 2 (1+1) to 12 (6+6). Since we want to know how many times we can expect the sum to be 7, we need to count the number of ways to get a sum of 7.
The pairs of numbers that add up to 7 are: (1,6), (2,5), (3,4), (4,3), (5,2), and (6,1). So, there are 6 ways to get a sum of 7.
Each time we roll the two number cubes, the probability of getting a sum of 7 is 6/36 or 1/6, since there are 6 possible outcomes that result in a sum of 7 out of a total of 36 possible outcomes.
Therefore, if we repeat this process 300 times, we can expect to get a sum of 7 approximately (1/6) x 300 = 50 times.
So we can expect the two cubes to add to exactly 7 about 50 times when rolled 300 times.
Explanation: