fix bug

app/helpers/exercises_helper.rb

@@ -369,11 +369,11 @@ module ExercisesHelper
           standard_answer = q.exercise_standard_answers.pluck(:exercise_choice_id).sort  #该问题的标准答案，可能有多个
           if user_answer_content == standard_answer  #答案一致,多选或单选才给分，答案不对不给分
             if standard_answer.count > 0
-              multi_each_score = (q.question_score / standard_answer.count)   #当多选答案正确时，每个answer的分数均摊。
+              q_score_1 = (q.question_score.to_f / standard_answer.count)   #当多选答案正确时，每个answer的分数均摊。
             else
-              multi_each_score = 0.0
+              q_score_1 = 0.0
             end
-            answers_content.update_all(:score => multi_each_score)
+            answers_content.update_all(:score => q_score_1)
             score1 = score1 + q.question_score
           end
         else
@@ -461,13 +461,13 @@ module ExercisesHelper
           "q_type":q.question_type,
           "q_position":q.question_number, #该问题的位置
           "stand_status":stand_answer,  #该问题是否正确,1为正确，0为错误
-          "user_score":user_scores  #每个问题的总得分
+          "user_score":user_scores.round(1)  #每个问题的总得分
       }
       ques_stand.push(ques_option)
     end
     total_score = score1 + score2 + score5
     {
-        "total_score":total_score,
+        "total_score":total_score.round(1),
         "stand_status":ques_stand
     }
   end
@@ -687,7 +687,7 @@ module ExercisesHelper
       exercise_user = exercise.exercise_users.find_by(user_id:user.id)
       time_mill = ex_time * 60   #转为秒
       exercise_end_time = exercise.end_time.present? ? exercise.end_time.to_i : 0
-      exercise_user_start = exercise_user.present? ? exercise_user.start_at.to_i : 0
+      exercise_user_start = exercise_user&.start_at.present? ? exercise_user.start_at.to_i : 0
       #用户未开始答题时，即exercise_user_start为0
       if exercise_user_start == 0
         if (exercise_end_time - time_now_i) > time_mill

app/views/exercises/index.json.jbuilder

@@ -23,7 +23,8 @@ if @exercises_count > 0
       ex_index = exercise_index_show(exercise,@course,@is_teacher_or,@current_user_)
       json.extract! exercise, :id, :exercise_name,:is_public,:created_at
       if @is_teacher_or == 2
-        json.time get_exercise_left_time(exercise,@current_user_)
+        second_left = get_exercise_left_time(exercise,@current_user_)
+        json.time second_left.present? ? (second_left / 60) : nil
       end
 
       json.exercise_status ex_index[:ex_status]