Run "sfdisk -l /dev/mmcblk0" from the terminal.

28,995,223,552 bytes for MyDocs
2,147,483,648 bytes for /home (and /opt, for applications)
805,306,368 bytes for swap

Total = 31,948,013,568 bytes. That's not quite 32,000,000,000 bytes.

Hey! We got shafted by 51,986,432 bytes! Where's my 50 megs gone? Oh partitioning boundary rounding probably.