diff --git a/Makefile b/Makefile
index c282388..a232501 100644
--- a/Makefile
+++ b/Makefile
@@ -1,12 +1,14 @@
 LD=-lusb-1.0
 CC=gcc
 CFLAGS=-Os
+LINKS=-lm
 
 usbscale: usbscale.c scales.h
-	$(CC) usbscale.c -o usbscale $(CFLAGS) $(LD)
+	$(CC) usbscale.c -o usbscale $(LINKS) $(CFLAGS) $(LD)
 
 lsscale: lsscale.c scales.h
 	$(CC) lsscale.c -o lsscale $(CFLAGS) $(LD)
 
-lsusb: lsusb.c
-	$(CC) lsusb.c -o lsusb $(CFLAGS) $(LD)
+clean:
+	rm -f lsscale
+	rm -f usbscale