Sign [Q] Storage space on tablet - confused


I have a Colorfly e708 Q1 tablet

According to the specifications it should have 8GB storage...
According to the tablet's systemís settings/storage menu, it has two internal storages (one being 1.48GB, the other being 3.76GB)
Now, I was wondering whether the two internal storages, the sum of which is 5.24GB, equal 8GB what is written in the specifications?!?
5.24GB = 8GB ?

In the android system's settings/storage my tablet shows this (yes, two internal storages are shown here):

internal storage
total space 1.48GB
available 1.29GB

internal storage
total space 3.76GB
available 3.70GB

I presume this means, that the system and installed apps take up 0.19GB and 0.06GB (sum 0.25GB) space from TOTAL and the available is what is left for me to use.
Now then, DOES this tablet HAVE 8GB or NOT?

Or do I get it wrong? Does the android system take (8GB-5.3GB=) 2.7GB space (?!?), which is absolutely not visible nor manageable for me?!
Then what takes up the 0.25GB space? All the installed APPs seen in the tabletís settings/applications menu use 188MB, I added them together

In the android system's settings/applications menu the tablet shows:

RAM 262MB used 479MB free (sum = 741MB; this should be 1GB according to the tablet's specifications... but at least this is near to 1GB)
internal storage 188MB used and 1.3GB free (sum = 1.48GB)
SD card storage 58MB used and 3.7GB free (sum = 3.76GB)

I don't have any external microSD inserted into the tablet, so the so called SD card storage is an internal storage as well, as the settings/storage menu showed earlier.

So in my opinion the 188MB and 58 MB (sum = 246MB = 0.25GB) is the space which the system and pre-installed apps used up.
Someone told me, that tablets like this one, have system restore partition, and other partitions I cannot see, without being rooted. OK, but if the whole system takes up 0.25GB, then why would such partitions need 2.7GB?!
Or where is 2.7GB?
I don't think that my other hypothesis, that the android system would use 2.7GB, is correct ... And also that situation would rise the question (for me) mentioned earlier: what is the 0.25GB?

Please help, because I'm thoroughly confused.

If I plug in the tablet to a PC, it sees only 3.7GB capacity.

In my opinion, (what I would call "storage space"), this tablet has only 3.76GB, that is cc 4GB storage . But mybe I'm not right... I don't know

PLEASE HELP!! I bought a tablet, that was declared to have 8GB capacity. Have I been deceived/cheated or not?