Fragmentation of IP packets, help clarify?

Question

Computer networks

I understood the general essence of IP fragmentation, this is when the network parameters MTU (Max Transmission Unit) from where the packets come from is less than the transmitted network, the bits related to the data are divided into several parts and sent further to the network.
The document RFC 791 https://rfc2.ru/791.rfc/16 has an algorithm for the fragmentation procedure and something is not clear to me.
The term NFC is defined as the number of fragments and below in the pseudocode it is equal to
NFC = (MTU - IHL * 4) / 8;
for example, with an MTU equal to 1500 bytes, the number of fragments with IHL = 20 bytes is 177.2 The
number 177.2 and the term NFC itself are not clear. After all, it is impossible to know the number of fragments without knowing the total size (TL) of the packet that needs to be fragmented. Can someone explain this point?

Answer 1

s/NFC/NFB/ (Number of Fragment Blocks, the number of data blocks per byte from which fragments are assembled).

It is not clear the number itself 177.2

All operations, where not specified separately, are integer, round down accordingly.

After all, it is impossible to know the number of fragments without knowing the total size (TL) of the packet that needs to be fragmented.

Upon receipt of a datagram, TL is known (IFL + data size), after calculating the route and the network interface from which it will be sent, the MTU will become known, then it is compared which is larger and fragmented at TL > MTU.