diff --git a/src/c/funktionen.h b/src/c/funktionen.h
index 8377a0d..037ed94 100644
--- a/src/c/funktionen.h
+++ b/src/c/funktionen.h
@@ -13,4 +13,7 @@ float cube(float x);
 // Function to calculate the cube root of a number
 float cubeRoot(float x);
 
+// Function to calculate the absolute value of a number
+float absolute(float x);
+
 #endif
\ No newline at end of file
diff --git a/src/test/test_funktionen.c b/src/test/test_funktionen.c
index 26c8030..0f0b22c 100644
--- a/src/test/test_funktionen.c
+++ b/src/test/test_funktionen.c
@@ -32,4 +32,9 @@ void test_cubeRoot(void) {
     // Add more test cases for different inputs and expected outputs
 }
 
+void test_absolute(void) {
+    float result = absolute(-5.0);
+    TEST_ASSERT_EQUAL_FLOAT(5.0, result);
+}
+
 #endif
\ No newline at end of file