diff --git a/misc/my_math_lib/mymath.c b/misc/my_math_lib/mymath.c
new file mode 100644
index 0000000..8a11739
--- /dev/null
+++ b/misc/my_math_lib/mymath.c
@@ -0,0 +1,7 @@
+#include <stdio.h>
+
+int plusone(int nr)
+{
+    return ++nr;
+} 
+
diff --git a/misc/my_math_lib/mymath.h b/misc/my_math_lib/mymath.h
new file mode 100644
index 0000000..1a0d448
--- /dev/null
+++ b/misc/my_math_lib/mymath.h
@@ -0,0 +1,3 @@
+/* Specification of mymath libs */
+
+extern int plusone(int nr);
diff --git a/misc/my_math_lib/test.c b/misc/my_math_lib/test.c
new file mode 100644
index 0000000..895bb02
--- /dev/null
+++ b/misc/my_math_lib/test.c
@@ -0,0 +1,7 @@
+#include <stdio.h>
+#include "mymath.h"
+
+int main()
+{
+    printf("Nr: %d\n", plusone(5));
+}