Final answer:
The fraction representing the number of girls in a class of x children is 16/x, which reflects the portion of girls in the whole class.
Step-by-step explanation:
In a class of x children, if there are 16 girls, the fraction that represents the number of girls is 16 over x, written as 16/x. This fraction indicates that there are 16 girls out of x total students in the class. To determine what fraction or percentage this represents, you would need the total number of students in the class (x), which is not provided in this scenario. Ratios and fractions are useful tools in representing parts of a larger whole, and they can be applied to numerous situations in mathematics, such as explaining the proportion of a subset within a set as expressed in fractions or calculating the probability of an event occurring.