diff --git a/1-setup.sh b/1-setup.sh
index aa53d7e..0714b88 100755
--- a/1-setup.sh
+++ b/1-setup.sh
@@ -271,7 +271,7 @@ fi
 
 SWAPSIZEgb=2
 
-SWAPSIZEmb=1024*$SWAPSIZEgb
+SWAPSIZEmb=$((1024*$SWAPSIZEgb))
 
 touch /swapfile
 dd if=/dev/zero of=/swapfile bs=1M count=$SWAPSIZEmb status=progress