diff --git a/readme.md b/readme.md
index 7f3fdcf..c5222c4 100644
--- a/readme.md
+++ b/readme.md
@@ -34,6 +34,10 @@ Update card Price
 		{$set:{'serra_updated':ISODate("2021-11-02T09:28:56.504Z")},
 		$push: {"serra_prices": { date: ISODate("2021-11-02T09:28:56.504Z"), value: 0.1 }}});
 
+Set value
+
+    db.cards.aggregate([{ $group: { _id: { set: "$set" }, value: { $sum: { $multiply: ["$prices.eur", "$serra_count"] } }, count: { $sum: 1 } } }])
+
 
 # MongoDB Operations
 
diff --git a/src/serra/root.go b/src/serra/root.go
index 7723027..c8edbac 100644
--- a/src/serra/root.go
+++ b/src/serra/root.go
@@ -75,15 +75,13 @@ func Sets() {
 	groupStage := bson.D{
 		{"$group", bson.D{
 			{"_id", "$setname"},
-			{"sum", bson.D{
-				{"$sum", "$prices.eur"},
-			}},
+			{"value", bson.D{{"$sum", bson.D{{"$multiply", bson.A{"$prices.eur", "$serra_count"}}}}}},
 		}},
 	}
 
 	sets, _ := coll.storage_aggregate(groupStage)
 	for _, set := range sets {
-		fmt.Printf("* %s (%.2f Eur)\n", set["_id"], set["sum"])
+		fmt.Printf("* %s (%.2f Eur)\n", set["_id"], set["value"])
 	}
 	storage_disconnect(client)