The phrase "large numbers of poor children" means that there are many kids who come from families that don't have a lot of money or resources. Full definition
When we apply these practices to large numbers of poor children with predictably horrific outcomes, it is a crime. (earlylearningfoundation.com)
Can we change the odds in significant ways for large numbers of poor children? (gse.harvard.edu)
The department proposed a rule that would require local school districts to give schools enrolling large numbers of poor children at least as much state and local money as other schools — thus prompting the letter. (nytimes.com)