diff --git a/src/time-stepping/state/ageinglawstateupdater.cc b/src/time-stepping/state/ageinglawstateupdater.cc
index 26cf0a026b27cc33e74501c0d3e900d41a2202a8..bbec51f20b6cc270ced25ff0208a536f87dbc61b 100644
--- a/src/time-stepping/state/ageinglawstateupdater.cc
+++ b/src/time-stepping/state/ageinglawstateupdater.cc
@@ -1,3 +1,5 @@
+#include <cmath>
+
 #include "ageinglawstateupdater.hh"
 #include "../../tobool.hh"
 
diff --git a/src/time-stepping/state/sliplawstateupdater.cc b/src/time-stepping/state/sliplawstateupdater.cc
index bfccec2feeedb850de11a37bd70dbaf181fa34d1..a31964d0f2bdf8d9efe1edc3717737c749168630 100644
--- a/src/time-stepping/state/sliplawstateupdater.cc
+++ b/src/time-stepping/state/sliplawstateupdater.cc
@@ -1,3 +1,5 @@
+#include <cmath>
+
 #include "sliplawstateupdater.hh"
 #include "../../tobool.hh"