diff --git a/app/src/main/java/net/pokeranalytics/android/calculus/interface/Datable.kt b/app/src/main/java/net/pokeranalytics/android/calculus/interface/Datable.kt
index 716c40fa..56fe1000 100644
--- a/app/src/main/java/net/pokeranalytics/android/calculus/interface/Datable.kt
+++ b/app/src/main/java/net/pokeranalytics/android/calculus/interface/Datable.kt
@@ -6,6 +6,6 @@ interface Datable {
 	var date: Date
 }
 
-interface DatableValue {
+interface DatableValue : Datable {
 	var value: Double
 }
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