diff --git a/play6 b/play6
index d04f0b0..ef119f5 100755
--- a/play6
+++ b/play6
@@ -123,7 +123,7 @@ list_set() {
 	dyn_set "${_list_set_id}_$2" "$3"
 }
 list_push() {
-	list_resize "$1" "$(("$(list_len $1)" +1))" || return
+	list_resize "$1" "$(($(list_len $1) +1))" || return
 	list_set "$1" "$(list_len $1)" "$2"
 }
 list_pop() {