diff --git a/src/minirechner.c b/src/minirechner.c
index 2ee4fd7..b5bf37b 100644
--- a/src/minirechner.c
+++ b/src/minirechner.c
@@ -1 +1,7 @@
+#include <stdio.h>
 #include "minirechner.h"
+
+//addieren
+float addieren(float a, float b) {
+    return a + b;
+}
\ No newline at end of file
diff --git a/src/minirechner.h b/src/minirechner.h
index 7be865b..63695c7 100644
--- a/src/minirechner.h
+++ b/src/minirechner.h
@@ -1,5 +1,6 @@
 #ifndef MINIRECHNER_H
 #define MINIRECHNER_H
 
+float addieren(float a, float b);
 
 #endif // MINIRECHNER_H
diff --git a/test/test_minirechner.c b/test/test_minirechner.c
index 30b6a4c..cce14b7 100644
--- a/test/test_minirechner.c
+++ b/test/test_minirechner.c
@@ -12,9 +12,11 @@ void tearDown(void)
 {
 }
 
-void test_minirechner_NeedToImplement(void)
+// test addition
+void test_minitaschenrechner_3_plus_4(void)
 {
-    TEST_IGNORE_MESSAGE("Need to Implement minirechner");
+    float result = addieren(3, 4);
+    TEST_ASSERT_EQUAL(7, result);
 }
 
 #endif // TEST