You can quickly determine that you need _at least_ seven items by summing the largest. It then happens that there are two possible seven-item solutions (468 solutions in total). To figure this out, I did in fact "just start adding."
That said, this problem isn't about mindlessly adding. It's about figuring out a way to systematically discover the answer. Most math challenge problems are designed with a method in mind; it's your job to figure that method out, and that's where the fun lies.
That said, this problem isn't about mindlessly adding. It's about figuring out a way to systematically discover the answer. Most math challenge problems are designed with a method in mind; it's your job to figure that method out, and that's where the fun lies.