diff --git a/app/helpers/exercises_helper.rb b/app/helpers/exercises_helper.rb
index b5168344d..bacb95309 100644
--- a/app/helpers/exercises_helper.rb
+++ b/app/helpers/exercises_helper.rb
@@ -213,9 +213,9 @@ module ExercisesHelper
         percent = (ex_total_score == 0.0 ? 0.0 : (answer_user_score / ex_total_score.to_f).round(3) * 100)  #正确率
 
         # percent = commit_user_ids > 0 ? (all_user_count / commit_user_ids.to_f).round(3)*100 : 0.0
-        user_right_count = effictive_users.where("score > 0.0").pluck(:user_id).uniq.size
-        user_wrong_counts = effictive_users.where("score < 0.0").pluck(:user_id).uniq.size
-        user_wrong_count = user_wrong_counts - user_right_count
+        user_right_count = effictive_users.where("score > 0.0").pluck(:user_id).uniq
+        user_wrong_counts = effictive_users.where("score < 0.0").pluck(:user_id).uniq
+        user_wrong_count = (user_wrong_counts - user_right_count).size
 
         if effictive_users_count > 0 && user_wrong_count >= 0
           wrong_percent =  (user_wrong_count / effictive_users_count.to_f ).round(3)