LINQ to SQL confusion

[lhq66063]

I'm trying to learn LINQ to SQL. I've run into something I just don't get. Here's the LINQ program:

Imports System.IOModule Module1    
Sub Main()
        Dim crs = New DataClasses1DataContext()
        Dim sw As New StringWriter()
        crs.Log = sw
        Dim reports = From report In crs.CRS_Report_Masters
                      Group report By report_id = report.Report_ID Into grouped = Group
                      Select New With {
                          .reportId = report_id,                          
                         .two = grouped.Sum(
                              Function(row) row.active_report * row.Report_ID)
                          }
        For Each report In reports
            Console.WriteLine("{0} {1}", report.reportId, report.two)
        Next        
MsgBox(sw.GetStringBuilder().ToString())    End SubEnd Module

Here's the SQL it produces:

SELECT SUM([t1].[value]) AS [two], [t1].[Report_ID] AS [reportId]  FROM (
      SELECT (-(CONVERT(Float,[t0].[active_report]))) *
            (CONVERT(Float,CONVERT(Float,[t0].[Report_ID]))) AS [value], [t0].[Report_ID]
      FROM [dbo].[CRS_Report_Master] AS [t0]
      ) AS [t1]  GROUP BY [t1].[Report_ID]
  -- Context: SqlProvider(Sql2008) Model: AttributedMetaModel Build: 4.0.30319.1

What I don't get is why there is a minus sign in the SQL before the math in the parentheses. I didn't specify that in the LINQ query.