calculating sum and add another table

Im trying to calculate sum of field(Marks)in table(marks) and sum value save in another table(wkall) field Sum1.
but it gives error message "Syntax error in query expression 'SELECT sum(marks) FROM data'."
Do you have any idea of this,Is my Sql Query has error..??
my code is like follow

 private void button1_Click(object sender, EventArgs e)
        {
            OleDbConnection myConnection = new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;" + @"data source=new.accdb");
            myConnection.Open();
           
            OleDbCommand myCommand = new OleDbCommand();
            myCommand.Connection = myConnection;

            myCommand.CommandText = "CREATE TABLE wkall([Sum1] double)";
            myCommand.ExecuteNonQuery();
            MessageBox.Show("Table Created Successfully");
                       
            OleDbCommand myCommand1 = new OleDbCommand();
            myCommand1.Connection = myConnection;

            myCommand1.CommandText = "INSERT INTO wkall(Sum1) VALUES(SELECT sum(marks) FROM data)";
            myCommand1.ExecuteNonQuery();
            MessageBox.Show("Data Inserted Successfully");
        }

data table id following format
Name(text) marks(double)