This is the 4444th most frequent Russian word.
военнослужащими
"Военнослужащими" means "military personnel" in English.
The word 'военнослужащими' is used as an instrumental plural form to denote the agents performing the action of the verb.
Военные учения проводились военнослужащими на полигоне.
The military exercises were conducted by servicemen at the training ground.
Here, the word 'военнослужащих' in the genitive plural form describes the group being quantified.
В этой войсковой части проходят службу более ста военнослужащих.
More than one hundred servicemen serve in this military unit.
'Военнослужащими' in this sentence is in the instrumental plural form, indicating the role the children have taken.