SQL Server 2017

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declare @pJSON varchar(max) = '
{
    "School": "MiddleSchool",
    "Password": "SchoolPassword",
    "Attributes": [
        {
            "Type": "Exam",
            "Value": "1"
        },
        {
            "Type": "Class",
            "Value": "11b"
        },
        {
            "Type": "Math",
            "Value": [
               {
                    "ExamDate": "2019-01-01",
                    "Points": 100,
                    "Grade": 10,
                    "Notes": "Good"
                }
                ,{
                    "ExamDate": "2019-01-01",
                    "Points": 200,
                    "Grade": 20,
                    "Notes": "Bad"
                }
            ]
        }   
    ]   
}   '
SELECT s2.[key]
      ,ExamValue = JSON_VALUE(s2.value, '$.ExamDate')
      ,Points    = JSON_VALUE(s2.value, '$.Points')
      ,Grade     = JSON_VALUE(s2.value, '$.Grade')
      ,Notes     = JSON_VALUE(s2.value, '$.Notes')
FROM OPENJSON(JSON_QUERY(@pJSON, N'$.Attributes')) s
CROSS APPLY OPENJSON(JSON_QUERY(s.value, N'$.Value')) s2

key	ExamValue	Points	Grade	Notes
0	2019-01-01	100	10	Good
1	2019-01-01	200	20	Bad

SELECT [value].*
FROM OPENJSON(JSON_QUERY(@pJSON, N'$.Attributes'))
CROSS APPLY OPENJSON(JSON_QUERY(value, N'$.Value'))
with    
(    
  ExamDate date      N'$.ExamDate', 
  Points int         N'$.Points',    
  Grade int          N'$.Grade',    
  Notes varchar(max) N'$.Notes'
) as [value];

ExamDate	Points	Grade	Notes
2019-01-01	100	10	Good
2019-01-01	200	20	Bad