HackerRank Functional Challenges HR F#: Lambda Calculus - Evaluating Expressions #4 Alex Netkachov Alex likes functional programming and algorithms. Apart from programming, his favourites are walking with his family in the parks and national trails and reading about universe and history. More posts by Alex Netkachov. Alex Netkachov 22 Sep 2017 • 1 min read This problem just checks how well you have got the idea of Church encoding while solving the previous problem. Compute the value of λx.λy.x(xy). Just by looking at the definition of the Church numerals it is easy to see that this function corresponds to number 2. And this is the right answer.