this is what i came up with
1024 b= 1kb
1024kb= 1Mb
1024Mb= 1Gb
the hard drive company rounds these numbers to 1000
1,073,741,824b = 1Gb actual space
1,000,000,000b = 1Gb rounded space
120,000,000,000/ 1,073,741,824 ≈ 111.8 Gb
your actually getting more than you should