According to statistics, too:

2:1 civilian:Hamas ratio according to the IDF, with 5000 from Hamas dead and 10,000 civilians dead [0]; Gaza’s population is about half under 18 [1].

So if you figure deaths among civilians are random, then about 5,000 Gazans under 18 are dead.

[0] - https://edition.cnn.com/2023/12/05/middleeast/israel-hamas-m...

[1] - https://www.npr.org/2023/10/18/1206897328/half-of-gazas-popu...