I have 4 worksheets
Master sheet
Project, Date, Sum of Description of change
100, 12/5/2006, Changed the Date and Changed the number
200, 12/5/2006, Changed the Date and Changed the number and Changed the ship to
300, 12/5/2006, Changed the number
400, 12/5/2006, Changed the Date and Changed the number
500, 12/5/2006, Changed the Date and Changed the number
600, 12/5/2006, Changed the Date and Changed the number

Sheet 2
Project, Date, Description of change
200, 12/5/2006, Changed the Date
300, 12/5/2006,
100, 12/5/2006, Changed the Date
400, 12/5/2006, Changed the Date
500, 12/5/2006, Changed the Date
600, 12/5/2006, Changed the Date

Sheet 3
Project, Date, Description of change
200, 12/5/2006, Changed the number
300, 12/5/2006, Changed the number
100, 12/5/2006, Changed the number
400, 12/5/2006, Changed the number
500, 12/5/2006, Changed the number
600, 12/5/2006, Changed the number

Sheet 4
Project, Date, Description of change
200, 12/5/2006, Changed the ship to
300, 12/5/2006,
100, 12/5/2006,
400, 12/5/2006,
500, 12/5/2006,
600, 12/5/2006

The above sheets have three columns: Project number, date, Description of change. I would like to some how automate Sum of Description of change (Column C) on Master sheet, to sum up the changes on sheet 2,3,4 according to the project number. Note the project number is going to be on different lines then the master sheet.