diff --git a/backend/src/generated-types/graphql.ts b/backend/src/generated-types/graphql.ts
index 41cc72cd9..b88243e75 100644
--- a/backend/src/generated-types/graphql.ts
+++ b/backend/src/generated-types/graphql.ts
@@ -35,7 +35,7 @@ export type CatalogClass = {
 
 export type CatalogItem = {
   __typename?: 'CatalogItem';
-  classes: Array<Maybe<CatalogClass>>;
+  classes: Array<CatalogClass>;
   description: Scalars['String'];
   gradeAverage?: Maybe<Scalars['Float']>;
   lastUpdated: Scalars['ISODate'];
@@ -55,7 +55,7 @@ export type Class = {
   number: Scalars['String'];
   primarySection: Section;
   raw: Scalars['JSONObject'];
-  sections: Array<Maybe<Section>>;
+  sections: Array<Section>;
   semester: Semester;
   session: Scalars['String'];
   status: Scalars['String'];
@@ -70,8 +70,8 @@ export type Class = {
 /** Info shared between Classes within and across semesters. */
 export type Course = {
   __typename?: 'Course';
-  classes: Array<Maybe<Class>>;
-  crossListing?: Maybe<Array<Maybe<Course>>>;
+  classes: Array<Class>;
+  crossListing?: Maybe<Array<Course>>;
   description: Scalars['String'];
   fromDate: Scalars['String'];
   gradeAverage?: Maybe<Scalars['Float']>;
@@ -81,7 +81,7 @@ export type Course = {
   number: Scalars['String'];
   prereqs?: Maybe<Scalars['String']>;
   raw: Scalars['JSONObject'];
-  sections: Array<Maybe<Section>>;
+  sections: Array<Section>;
   subject: Scalars['String'];
   subjectName: Scalars['String'];
   title: Scalars['String'];
@@ -202,7 +202,7 @@ export type Query = {
    *
    * Used primarily in the catalog page.
    */
-  catalog?: Maybe<Array<Maybe<CatalogItem>>>;
+  catalog?: Maybe<Array<CatalogItem>>;
   class?: Maybe<Class>;
   course?: Maybe<Course>;
   /**
@@ -210,7 +210,7 @@ export type Query = {
    *
    * Useful for searching for courses.
    */
-  courseList?: Maybe<Array<Maybe<CourseListItem>>>;
+  courseList?: Maybe<Array<CourseListItem>>;
   grade?: Maybe<Grade>;
   /** @deprecated test */
   ping: Scalars['String'];
@@ -310,8 +310,8 @@ export type Section = {
   days?: Maybe<Array<Scalars['Boolean']>>;
   enrollCount: Scalars['Int'];
   enrollMax: Scalars['Int'];
-  enrollmentHistory?: Maybe<Array<Maybe<EnrollmentDay>>>;
-  instructors?: Maybe<Array<Maybe<Instructor>>>;
+  enrollmentHistory?: Maybe<Array<EnrollmentDay>>;
+  instructors?: Maybe<Array<Instructor>>;
   kind: Scalars['String'];
   lastUpdated: Scalars['ISODate'];
   location?: Maybe<Scalars['String']>;
@@ -550,7 +550,7 @@ export type CatalogClassResolvers<ContextType = any, ParentType extends Resolver
 };
 
 export type CatalogItemResolvers<ContextType = any, ParentType extends ResolversParentTypes['CatalogItem'] = ResolversParentTypes['CatalogItem']> = {
-  classes?: Resolver<Array<Maybe<ResolversTypes['CatalogClass']>>, ParentType, ContextType>;
+  classes?: Resolver<Array<ResolversTypes['CatalogClass']>, ParentType, ContextType>;
   description?: Resolver<ResolversTypes['String'], ParentType, ContextType>;
   gradeAverage?: Resolver<Maybe<ResolversTypes['Float']>, ParentType, ContextType>;
   lastUpdated?: Resolver<ResolversTypes['ISODate'], ParentType, ContextType>;
@@ -569,7 +569,7 @@ export type ClassResolvers<ContextType = any, ParentType extends ResolversParent
   number?: Resolver<ResolversTypes['String'], ParentType, ContextType>;
   primarySection?: Resolver<ResolversTypes['Section'], ParentType, ContextType>;
   raw?: Resolver<ResolversTypes['JSONObject'], ParentType, ContextType>;
-  sections?: Resolver<Array<Maybe<ResolversTypes['Section']>>, ParentType, ContextType>;
+  sections?: Resolver<Array<ResolversTypes['Section']>, ParentType, ContextType>;
   semester?: Resolver<ResolversTypes['Semester'], ParentType, ContextType>;
   session?: Resolver<ResolversTypes['String'], ParentType, ContextType>;
   status?: Resolver<ResolversTypes['String'], ParentType, ContextType>;
@@ -583,8 +583,8 @@ export type ClassResolvers<ContextType = any, ParentType extends ResolversParent
 };
 
 export type CourseResolvers<ContextType = any, ParentType extends ResolversParentTypes['Course'] = ResolversParentTypes['Course']> = {
-  classes?: Resolver<Array<Maybe<ResolversTypes['Class']>>, ParentType, ContextType, Partial<CourseClassesArgs>>;
-  crossListing?: Resolver<Maybe<Array<Maybe<ResolversTypes['Course']>>>, ParentType, ContextType>;
+  classes?: Resolver<Array<ResolversTypes['Class']>, ParentType, ContextType, Partial<CourseClassesArgs>>;
+  crossListing?: Resolver<Maybe<Array<ResolversTypes['Course']>>, ParentType, ContextType>;
   description?: Resolver<ResolversTypes['String'], ParentType, ContextType>;
   fromDate?: Resolver<ResolversTypes['String'], ParentType, ContextType>;
   gradeAverage?: Resolver<Maybe<ResolversTypes['Float']>, ParentType, ContextType>;
@@ -594,7 +594,7 @@ export type CourseResolvers<ContextType = any, ParentType extends ResolversParen
   number?: Resolver<ResolversTypes['String'], ParentType, ContextType>;
   prereqs?: Resolver<Maybe<ResolversTypes['String']>, ParentType, ContextType>;
   raw?: Resolver<ResolversTypes['JSONObject'], ParentType, ContextType>;
-  sections?: Resolver<Array<Maybe<ResolversTypes['Section']>>, ParentType, ContextType, Partial<CourseSectionsArgs>>;
+  sections?: Resolver<Array<ResolversTypes['Section']>, ParentType, ContextType, Partial<CourseSectionsArgs>>;
   subject?: Resolver<ResolversTypes['String'], ParentType, ContextType>;
   subjectName?: Resolver<ResolversTypes['String'], ParentType, ContextType>;
   title?: Resolver<ResolversTypes['String'], ParentType, ContextType>;
@@ -666,10 +666,10 @@ export type MutationResolvers<ContextType = any, ParentType extends ResolversPar
 };
 
 export type QueryResolvers<ContextType = any, ParentType extends ResolversParentTypes['Query'] = ResolversParentTypes['Query']> = {
-  catalog?: Resolver<Maybe<Array<Maybe<ResolversTypes['CatalogItem']>>>, ParentType, ContextType, RequireFields<QueryCatalogArgs, 'term'>>;
+  catalog?: Resolver<Maybe<Array<ResolversTypes['CatalogItem']>>, ParentType, ContextType, RequireFields<QueryCatalogArgs, 'term'>>;
   class?: Resolver<Maybe<ResolversTypes['Class']>, ParentType, ContextType, RequireFields<QueryClassArgs, 'classNumber' | 'courseNumber' | 'subject' | 'term'>>;
   course?: Resolver<Maybe<ResolversTypes['Course']>, ParentType, ContextType, RequireFields<QueryCourseArgs, 'courseNumber' | 'subject'>>;
-  courseList?: Resolver<Maybe<Array<Maybe<ResolversTypes['CourseListItem']>>>, ParentType, ContextType>;
+  courseList?: Resolver<Maybe<Array<ResolversTypes['CourseListItem']>>, ParentType, ContextType>;
   grade?: Resolver<Maybe<ResolversTypes['Grade']>, ParentType, ContextType, RequireFields<QueryGradeArgs, 'courseNum' | 'subject'>>;
   ping?: Resolver<ResolversTypes['String'], ParentType, ContextType>;
   scheduleByID?: Resolver<Maybe<ResolversTypes['Schedule']>, ParentType, ContextType, RequireFields<QueryScheduleByIdArgs, 'id'>>;
@@ -700,8 +700,8 @@ export type SectionResolvers<ContextType = any, ParentType extends ResolversPare
   days?: Resolver<Maybe<Array<ResolversTypes['Boolean']>>, ParentType, ContextType>;
   enrollCount?: Resolver<ResolversTypes['Int'], ParentType, ContextType>;
   enrollMax?: Resolver<ResolversTypes['Int'], ParentType, ContextType>;
-  enrollmentHistory?: Resolver<Maybe<Array<Maybe<ResolversTypes['EnrollmentDay']>>>, ParentType, ContextType>;
-  instructors?: Resolver<Maybe<Array<Maybe<ResolversTypes['Instructor']>>>, ParentType, ContextType>;
+  enrollmentHistory?: Resolver<Maybe<Array<ResolversTypes['EnrollmentDay']>>, ParentType, ContextType>;
+  instructors?: Resolver<Maybe<Array<ResolversTypes['Instructor']>>, ParentType, ContextType>;
   kind?: Resolver<ResolversTypes['String'], ParentType, ContextType>;
   lastUpdated?: Resolver<ResolversTypes['ISODate'], ParentType, ContextType>;
   location?: Resolver<Maybe<ResolversTypes['String']>, ParentType, ContextType>;
diff --git a/backend/src/modules/catalog/controller.ts b/backend/src/modules/catalog/controller.ts
index e9247a9d6..6c5b7ac3b 100644
--- a/backend/src/modules/catalog/controller.ts
+++ b/backend/src/modules/catalog/controller.ts
@@ -160,17 +160,46 @@ export function getPrimarySection(id: string, term: TermInput, classNumber: stri
 }
 
 export function getClassSections(id: string, term: TermInput, classNumber: string) {
+    // for associated sections with a lecture. Lecture assumed to be of form 00x
     return SectionModel
         .find({
             "class.course.identifiers": matchCsCourseId(id),
             "class.session.term.name": termToString(term),
-            "class.number": classNumber
+            $or: [
+                {"class.number": {$regex: new RegExp("^"+classNumber[classNumber.length-1])}},
+                {"class.number": "999"}
+            ]
         })
         .lean()
         .then(s => s.map(formatSection))
 }
 
-export function getCourse(subject: string, courseNumber: string, term?: TermInput | null) {
+async function getCourseFromFilter(filter: any, term?: TermInput | null, info?: GraphQLResolveInfo | null) {
+
+    const course = await CourseModel
+        .findOne(filter)
+        .sort({ fromDate: -1 })
+        .lean()
+        .then(c => formatCourse(c, term))
+
+    if (info && getChildren(info).includes("gradeAverage")) {
+
+        const grades : GradeType[] = []
+        const gradesQuery = await GradeModel.find({
+            "CourseSubjectShortNm": course.raw.classSubjectArea?.description ?? course.raw.subjectArea?.description,
+            "CourseNumber": course.raw.catalogNumber?.formatted
+        }, {GradeNm: 1, EnrollmentCnt: 1})
+        for (const grade of gradesQuery) {
+            grades.push(grade)
+        }
+        course.gradeAverage = await getAverage(grades)
+
+    }
+
+    return course
+}
+
+export function getCourse(subject: string, courseNumber: string, term?: TermInput | null, info?: GraphQLResolveInfo) {
     const filter: any = {
         "classSubjectArea.code": subject,
         "catalogNumber.formatted": courseNumber
@@ -180,11 +209,7 @@ export function getCourse(subject: string, courseNumber: string, term?: TermInpu
         filter.fromDate = { $lte: getTermStartMonth(term) }
     }
 
-    return CourseModel
-        .findOne(filter)
-        .sort({ fromDate: -1 })
-        .lean()
-        .then(c => formatCourse(c, term))
+    return getCourseFromFilter(filter, term, info)
 }
 
 export function getCourseById(id: string, term?: TermInput | null) {
@@ -196,11 +221,7 @@ export function getCourseById(id: string, term?: TermInput | null) {
         filter.fromDate = { $lte: getTermStartMonth(term) }
     }
 
-    return CourseModel
-        .findOne(filter)
-        .sort({ fromDate: -1 })
-        .lean()
-        .then(c => formatCourse(c, term))
+    return getCourseFromFilter(filter, term)
 }
 
 export function getCourseClasses(id: string, term?: TermInput | null) {
@@ -218,6 +239,20 @@ export function getCourseClasses(id: string, term?: TermInput | null) {
         .then(c => c.map(formatClass))
 }
 
+export function getCourseSections(id: string, term?: TermInput | null) {
+    const filter: any = {
+        "class.course.identifiers": matchCsCourseId(id),
+    }
+
+    if (!isNil(term)) {
+        filter["class.session.term.name"] = termToString(term)
+    }
+    return SectionModel
+        .find(filter)
+        .lean()
+        .then(s => s.map(formatSection))
+}
+
 export function getCrossListings(displayNames: string[], term?: TermInput | null) {
     return displayNames.map(name => {
         const filter: any = {
diff --git a/backend/src/modules/catalog/resolver.ts b/backend/src/modules/catalog/resolver.ts
index c46593a8d..875f31250 100644
--- a/backend/src/modules/catalog/resolver.ts
+++ b/backend/src/modules/catalog/resolver.ts
@@ -1,10 +1,10 @@
 import { CatalogModule } from "./generated-types/module-types";
-import { getCatalog, getClass, getClassById, getClassSections, getCourse, getCourseById, getCourseClasses, getCourseList, getCrossListings, getPrimarySection, getSection } from "./controller"
+import { getCatalog, getClass, getClassById, getClassSections, getCourse, getCourseById, getCourseClasses, getCourseList, getCourseSections, getCrossListings, getPrimarySection, getSection } from "./controller"
 
 const resolvers: CatalogModule.Resolvers = {
     Query: {
         catalog: (_, args, __, info) => getCatalog(args.term, info),
-        course: (_, args) => getCourse(args.subject, args.courseNumber, args.term),
+        course: (_, args, __, info) => getCourse(args.subject, args.courseNumber, args.term, info),
         class: (_, args) => getClass(args.subject, args.courseNumber, args.term, args.classNumber),
         section: (_, args) => getSection(args.subject, args.courseNumber, args.term, args.classNumber, args.sectionNumber),
         courseList: getCourseList,
@@ -49,6 +49,10 @@ const resolvers: CatalogModule.Resolvers = {
         crossListing: (parent) => {
             const cl = parent.crossListing as any
             return getCrossListings(cl.displayNames, cl.term)
+        },
+        sections: (parent, { term }) => {
+            const c = parent.classes as any
+            return getCourseSections(c, term)
         }
     }
 }
diff --git a/backend/src/modules/catalog/typedefs/catalog.ts b/backend/src/modules/catalog/typedefs/catalog.ts
index c37859582..96886a54d 100644
--- a/backend/src/modules/catalog/typedefs/catalog.ts
+++ b/backend/src/modules/catalog/typedefs/catalog.ts
@@ -11,24 +11,23 @@ type Query {
     
     Used primarily in the catalog page.
     """
-    catalog(term: TermInput!): [CatalogItem]
+    catalog(term: TermInput!): [CatalogItem!]
 
     """
     Get a list of all course names across all semesters. 
     
     Useful for searching for courses.
     """
-    courseList: [CourseListItem]
+    courseList: [CourseListItem!]
 }
 
 """
 Info shared between Classes within and across semesters.
 """
 type Course @cacheControl(maxAge: 1) {
-    classes(term: TermInput): [Class]!
-    crossListing: [Course]
-    sections(term: TermInput, primary: Boolean): [Section]!
-
+    classes(term: TermInput): [Class!]!
+    crossListing: [Course!]
+    sections(term: TermInput, primary: Boolean): [Section!]!
     description: String!
     fromDate: String!
     gradeAverage: Float
@@ -51,7 +50,7 @@ Data for a specific class in a specific semester. There may be more than one Cla
 type Class @cacheControl(maxAge: 1) {
     course: Course!
     primarySection: Section!
-    sections: [Section]!
+    sections: [Section!]!
 
     description: String
     enrollCount: Int!
@@ -77,7 +76,7 @@ Sections are each associated with one Class.
 type Section @cacheControl(maxAge: 1) {
     class: Class!
     course: Course!
-    enrollmentHistory: [EnrollmentDay]
+    enrollmentHistory: [EnrollmentDay!]
 
     ccn: Int!
     dateEnd: String
@@ -85,7 +84,7 @@ type Section @cacheControl(maxAge: 1) {
     days: [Boolean!]
     enrollCount: Int!
     enrollMax: Int!
-    instructors: [Instructor]
+    instructors: [Instructor!]
     kind: String!
     location: String
     notes: String
@@ -117,7 +116,7 @@ type CatalogItem @cacheControl(maxAge: 1) {
     number: String!
     title: String!
     description: String!
-    classes: [CatalogClass]!
+    classes: [CatalogClass!]!
     gradeAverage: Float
 
     lastUpdated: ISODate!