gb -> mb -> kb -> b -> bit
13mb = 13 * (2^10)^2 = 13631488 b
128mb = 2^7 mb, 1 gb = 2^10 mb, 2^7/2^10 = 0.125, 128mb = 0.125gb
6.12mb = 6.12 * 2^23 = 51338281 bit
0.02gb -> kb, 1gb = 2^20 kb, 2^20 * 0.02 = 20971 kb
90112 bit = 90112 / 2^13 = 11kb