Under Armour Security Engineer interview questions

They wanted to see if I could build and implement a web-based service on the fly. This task can be performed by a competent programmer, so I assume they got one. Task: White board a program in your favorite programming language, write it, run it, secure it and criticize it. Instruction was to create web service, google web, enter a&b, and service calc c=a/b, Return value from website. This interview occurred *before* the massive data breach, so not sure if this is in practice anymore.