Bytes into Kilobytes:
256 << 10 == 256 * 1024
Bytes into Megabytes:
256 << 20 == 256 * 1024 * 1024


One shift to left is "multiplied by 2", so 10 shifts are 2^10 = 1024, which is the "byte to kilobyte" formula... no clue if that's understandable now xD