BA II plus - Remaining book value and remaining depreciable value

CFA Level I
#1

Guys, I was just trying to get familiar with the depreciation mode of calculator and came across these two terms: Remaining book value and remaining depreciable value What is the remaining depreciable value? Thanks

#2

Remaining book value = remaining depreciable value + salvage value

#3

So what do you infer from remaining depreciable value? Thanks S