For a constant \(t\in \mathbb {N}\) , we consider the problem of counting the number of t-cliques mod 2 in a given graph. We show that this problem is not easier than determining whether a given graph contains a t-clique, and present a simple worst-case to average-case reduction for it. The reduction runs in linear time when graphs are presented by their adjacency matrices, and average-case is with respect to the uniform distribution over graphs with a given number of vertices. The foregoing results were previously obtained by Boix-Adsera, Brennan, and Bresler (FOCS’19), using a more complex worst-case to average-case reduction. The current note has the advantage of providing a short and self-contained presentation of the foregoing results.