Final answer:
The range of the ages of the four children is 5 years.
Step-by-step explanation:
The range of a set of numbers is the difference between the highest and lowest values in the set. In this case, the highest age is 17 and the lowest age is 12. So, the range of the ages of the four children is 17 - 12 = 5. Therefore, the range of the ages is 5 years.