Finding the sum of items across multiple rows and values

[Mrcas]

I'm trying to figure out what combination of sumproduct to use to get the quantity total from the 'Inventory' sheet to the 'Weekly Report'.
I'm hitting a wall since Inventory lists multiple of the same style while the Weekly Report has just one for the total.
Any help would be appreciated, it's been a while and I'm trying to refresh my memory but I hit a wall with this one. http://[URL=http://s1343.photobucke...ums/o781/Cas_Cas/image_zpsuqcaqsf9.jpeg[/IMG][/URL]

 

[Mrcas]

Goofed up the photo link....
http://i1343.photobucket.com/albums/o781/Cas_Cas/image_zpsuqcaqsf9.jpeg