A cube has 6 faces.
Since Joanna roles a number cube, the possible outcomes are numbers from 1 to 6:
1, 2, 3, 4, 5, 6
The greatest possible outcome is 6.
We can see that all possible outcome values are numbers less than 7
Therefore, the certain outcome is rolling a number less than 7
ANSWER:
c. Rolling a number less than 7
