question about using pack, unpack, and prepend with floating point numbers

hello max community,
i've started learning max recently, and have been going through a few max tutorials from the max help section. i'm currently on the "mouse drawing" tutorial, but i've made a small patch and there's one small thing about it that doesn't make sense to me.

i've read that the arguments for the pack and unpack objects can be mixed and matched with different "types" of arguments, such as integers, floating point numbers, and symbols, in any order. so i tried to come up with a small patch as a way to show myself the concept.

i set up a patch with a message box that contains a list with a symbol, integer, and floating point number in a message. this message gets unpacked, and then packed again, sent through the prepend, and finally printed in the max window.

when i look at the max window it prints what i expect it too, except for one problem. i chose 64.3 as my floating point number to be sent through, but when it gets processed, it prints 64.300003 in the floating point number box and in the max window. why doesn't it just print 64.3 like i have it? just a small question i have before i move on further. any insight on this would be appreciated, thanks.