: This usually means one of the parts (like .002 ) is missing or the download was interrupted.
: Often indicates a version, a 4x zoom/resolution, or that it is the 4th iteration of the file. BD Mag-5-1 (plus 2 and 3)-4x.7z.001
Do you have the (like .002 or .003) saved in the same folder as this file? ELEMENTS OF ALGEBRA, - Wikimedia Commons : This usually means one of the parts (like