Database
[{"_id":1,"isCaptain":true,"points":0},{"_id":2,"isCaptain":false,"points":0}]
Query
db.collection.update({_id:1},[{"$set":{"points":{"$cond":{"if":{"$eq":["$isCaptain",true]},"then":{"$multiply":[100,2]},"else":100}}}}])