Some issues related with Unified State Examination in Informatics in Russian Federation: Как могла бы звучать Задача 12 в ЕГЭ Информатика на сегодняшний день

The next post is an attempt to slightly change the eternal theme,
which task 12 of EGE Informatics contains from immemorial times

Per https://www.lifewire.com/cidr-classless-domain-routing-818375
CIDR is an acronym for Classless Inter-Domain Routing. CIDR was developed
in the 1990s as a standard scheme for routing network traffic across the internet.
Why Use CIDR?
Before CIDR technology was developed, internet routers managed network
traffic based on the class of IP addresses. In this system, the value
of an IP address determines its subnetwork for the purposes of routing.
CIDR is an alternative to traditional IP subnetting.
It organizes IP addresses into subnetworks independent of the value of
the addresses themselves. CIDR is also known as supernetting, as it
effectively allows multiple subnets to be grouped together for network routing.

See also Classful vs. Classless Routing - Cisco Support Community
Mentioned document clearly demonstrates what kind of trouble might cause classfull routing approach. Notice also that :-

Would you have problems reading English, see Russian post

Бесклассовая адресация CIDR и маски переменной длины VLSM
Выдержка из текста и рисунки статьи на русском

Использование CIDR и VLSM не только предотвращает пустую трату адресов, но и способствует агрегации маршрутов или суммированию. Без суммирования маршрутов Интернет перестал бы развиваться уже в конце 90-х годов. Рисунок иллюстрирует как суммирование сокращает нагрузку на маршрутизаторы.

Aggregation routes via VLSM

Количество адресов в подсети не равно количеству возможных узлов.
Нулевой адрес IP резервируется для идентификации подсети, последний -
в качестве широковещательного адреса, таким образом в реально действующих сетях возможно количество узлов на два меньшее количества адресов.
Простой пример :-

Выполняя на маршрутизаторе RIPv2,OSPF,IS-IS ( любой протокол поддерживающий CIDR ).

It is fairly simple to convert the samples (pictures 1,3) above into one or variety of tasks 12-th for EGE Informatics which won't look as the ghosts came from previous century.

CIDR Range is 192.168.100.0/22. Questions :-
1. What is the network mask ?
2. What are wildcard bits ?
3. How much is total host Count ?

Easy to see that third octet is 11111100 (binary) = 252 (decimal)
Obviously first and second octets are 11111111 (binary) = 255 (decimal)
fourth is 00000000 (binary) due to (4*8) - (2*8+6) = 10
Number of host on suibnet 2^10 = 1024
Netmask 255.255.252.0
Wildcard bits = 0.0.(255-252).255 =0.0.3.255

    Broadcast address 192.168.103.255
Default gateway      192.168.100.1

CIDR Range is 172.24.4.224/28. Questions :-
1. What is the network mask ?
2. What are wildcard bits ?
3. How much is total host Count ?

Easy to see that fourth octet is 11110000 (binary) = 240 (decimal)
Obviously first, second,third octets are 11111111 (binary) = 255 (decimal)
due to (4*8) - (3*8+4) =4
Number of host on suibnet 2^4 = 16
Netmask 255.255.255.240
Wildcard bits = 0.0.0.(255-240) = 0.0.0.15