How many {armament} are to/by {aircraft} ?
What are all the kinds of armaments on this aircraft?
How many armament does the aircraft has?
SELECT ( COUNT ( ?k ) AS ?h ) { ?k property:armament resource:aircraft }
SELECT (COUNT(?sub) AS ?subs ) {
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#subject> ?sub .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#predicate> <http://www.wikidata.org/entity/P520> .
?statement <http://www.w3.org/1999/02/22-rdf-syntax-ns#object> http://wikidata.dbpedia.org/resource/Q11436 .
} 

SELECT (COUNT(?sub) AS ?value ) { ?sub wdt:P520 wd:Q11436 }
10