Numbers have many means of access into dreams. The most common is through objects. For example, sometimes you have stones in your hand. Another time, a stranger may give you stones. How many stones does the stranger give you?
Another means of access to numbers is through time. This time could be generalized in that it feels like about one hour. You may look at a digital watch and see an exact time, maybe even a nonsense time. It may be a particular date. In any case, the occurrence of numbers in dreams is an interesting study.
While numerology is a field of study in itself, there are general conclusions that can be drawn about dream numbers that may be helpful. First, you need to ascertain how the number got into your head in relationship to the dream.
Adding the digits together and discerning a difference between numbers, squares, and cubes is another way to handle numbers in dreams. Our minds are capable of pretty tricky internal math, given the chance. The problem with math and waking life is that able minds are talked out of successful math efforts due to common misconceptions and other illogical fears.
The study of numerology is a good complement to your dream interpretations, especially if numbers come up often.