This tag is for basic questions about the study of finite or countable discrete structures — specifically how to count or enumerate elements in a set (perhaps of all possibilities) or any subset. It includes questions on permutations, combinations, bijective proofs, and generating functions. ...
A certain chessboard is infinite in size. There is a frog sitting in the center of every square. After a certain time, all the frogs jump such that They may jump to any possible square in the ...