Add a calculator that's easier to use than bc
diff --git a/modules/calculator.nix b/modules/calculator.nix
new file mode 100644
index 0000000..7410214
--- /dev/null
+++ b/modules/calculator.nix
@@ -0,0 +1,3 @@
+{pkgs, ...}: {
+  home.home.packages = [pkgs.wcalc];
+}