[{"prediction":{"B-experience":["5"]}},{"prediction":{"B-experience":["9"]}},{"prediction":{"B-experience":["1"]}},{"prediction":{"B-experience":["6"]}}]

db.collection.aggregate([{$project:{predictionBexperience:{"$arrayElemAt":["$prediction.B-experience",0]}}},{$project:{predictionBexperience:{"$toInt":"$predictionBexperience"}}},{$match:{predictionBexperience:{$gt:2,$lte:7}}}])