Question: What is the method for determining which developing country has 3.23e+08 children out of school?
Paraphrase: Which method is used to figure out, out of school kids numbering 3.23e+08 in developing countries  ?
SPARQL (Wikidata): SELECT ?value WHERE { wd:Q177323 p:P2573 ?s . ?s ps:P2573 ?x filter(contains(?x , '3.23e+08')) . ?s pq:P459 ?value}