This is the 3990th most frequent Russian word.
каждому
"To everyone" or "to each."
In this usage, 'каждому' functions as a dative case to indicate 'to each' or 'for every', showing the necessity directed at every person.
Каждому человеку нужно заботиться о своем здоровье.
Every person needs to take care of their health.
Here, 'каждому' in the dative case marks the recipients of the attention, emphasizing inclusivity towards every student individually.
Учитель уделяет внимание каждому ученику в классе.
The teacher pays attention to every student in the class.
The word 'каждому' is used to specify that the necessity applies inclusively to each member of the group 'us', represented in the dative case.