Can someone tell me how to read these damn sizes.

i mean, i prefer to see sizes in MB but that is not the case when you do an ls -l on directories. i have a had time converting these to MB

just for verification purposes, what would a directory size like this = 3499990308 represent in MB
or something like this 29994??

or is there a rule i can follow to be able to calculate this crap on my own? honestly, if any revision needs to be made to unix, it should be the ability to make all these sizes VERY easy to read. unix is complicated enough to be wasting time on this nonsense