diff --git a/chapter_07/Makefile b/chapter_07/Makefile
index e831f5c..194012e 100644
--- a/chapter_07/Makefile
+++ b/chapter_07/Makefile
@@ -5,7 +5,7 @@ all: lispy
 
 
 %: %.c
-	cc -std=c11 -Wall $@.c ${MPC_DIR}/mpc.c -ledit -o $@
+	cc -std=c11 -Wall $@.c ${MPC_DIR}/mpc.c -ledit -lm -o $@
 
 
 .PHONY: clean
diff --git a/chapter_08/Makefile b/chapter_08/Makefile
index e831f5c..194012e 100644
--- a/chapter_08/Makefile
+++ b/chapter_08/Makefile
@@ -5,7 +5,7 @@ all: lispy
 
 
 %: %.c
-	cc -std=c11 -Wall $@.c ${MPC_DIR}/mpc.c -ledit -o $@
+	cc -std=c11 -Wall $@.c ${MPC_DIR}/mpc.c -ledit -lm -o $@
 
 
 .PHONY: clean
diff --git a/chapter_09/Makefile b/chapter_09/Makefile
index e831f5c..8f3963f 100644
--- a/chapter_09/Makefile
+++ b/chapter_09/Makefile
@@ -4,8 +4,8 @@ MPC_DIR := ../mpc
 all: lispy
 
 
-%: %.c
-	cc -std=c11 -Wall $@.c ${MPC_DIR}/mpc.c -ledit -o $@
+%: %.c %.h
+	cc -std=c11 -Wall $@.c ${MPC_DIR}/mpc.c -ledit -lm-o $@
 
 
 .PHONY: clean
diff --git a/chapter_10/Makefile b/chapter_10/Makefile
index e831f5c..3f4c2ea 100644
--- a/chapter_10/Makefile
+++ b/chapter_10/Makefile
@@ -4,8 +4,8 @@ MPC_DIR := ../mpc
 all: lispy
 
 
-%: %.c
-	cc -std=c11 -Wall $@.c ${MPC_DIR}/mpc.c -ledit -o $@
+%: %.c %.h
+	cc -std=c11 -Wall -Wextra $@.c ${MPC_DIR}/mpc.c -ledit -lm -o $@
 
 
 .PHONY: clean