[{"counter":"APPLE","fsgeneral":{"0":{"fye":"Mar-01","dilutedShares":{"value":10}},"1":{"fye":"Mar-02","dilutedShares":{"value":10}}},"balancesheet":{"0":{"fye":"Mar-01","shareholderFund":{"value":200}},"1":{"fye":"Mar-02","shareholderFund":{"value":400}}}}]

db.collection.aggregate([{$project:{counter:1,output:{$arrayToObject:{$map:{input:{$objectToArray:"$balancesheet"},as:"a",in:{k:"$$a.k",v:{fye:"$$a.v.fye",bookvalue:{value:{$reduce:{input:{$objectToArray:"$fsgeneral"},initialValue:0,in:{$cond:[{$eq:["$$this.k","$$a.k"]},{$divide:["$$a.v.shareholderFund.value","$$this.v.dilutedShares.value"]},"$$value"]}}}}}}}}}}}])