This problem isn't specitic enough. I don't know what it wants me to do. I literally don't know what the problem is asking. A lot of the problems in this section "Java" are very specific, and do a great job to introduce new concepts, so that's what I expect. Furthermore, I do not understand the code. There is an interface that has not been implemented, then another class called "MyMath" that calls methods from that interface? If I don't understand how this code even works, how am I supposed to complete it? If I have never used a Lambda expression in my life, I should be able to read the problem, do a bit of research, then solve it.