ok, heads spinning, just need a straight answer...

ok, one more thing, i'm trying to understand offset vrs backspacing, so you subtract the offset from the backspacing? i don't get it... for example, the rims im looking at is

Manufacturer: AmericanMuscle Wheels
Style: FR500
Size: 18x10
Finish: Black
Placement: Rear Only
Centercap Size: Large (2-1/2")
Back Spacing: 6.3" (161mm)
Offset: +22mm (0.9")
Bolt Pattern: 5x4.5" (5x114.3mm)
Weight: 26.5 lbs
Material: Aluminum
Lip Size : 1.75"


don't understand...read it on a few sites, anyone explain it in plane english to me?