You volunteer to help drive children at a charity event to the zoo, but you can fit only 7 of the 17 children present in your van. How many different groups of 7 children can you drive?
How many different groups of 7 children can you drive?

Step 1 ：This is a combination problem. We are choosing 7 children out of 17, without regard to the order in which we choose them. The formula for combinations is: $$C(n,k)=\frac{n!}{k!(n-k)!}$$ where n is the total number of items, k is the number of items to choose, and "!" denotes factorial, which is the product of all positive integers up to that number.

Step 2 ：In this case, n = 17 (the total number of children) and k = 7 (the number of children we can fit in the van).

Step 3 ：Substituting the values into the formula, we get $$C(17,7)=\frac{17!}{7!(17-7)!}$$

Step 4 ：Solving the above expression, we get the number of combinations as 19448.

Step 5 ：Final Answer: The number of different groups of 7 children you can drive is $\boxed{{\displaystyle 19448}}$.