diff --git a/build/test/cache/test_sqrt.c b/build/test/cache/test_sqrt.c
new file mode 100644
index 0000000..2fc2a2d
--- /dev/null
+++ b/build/test/cache/test_sqrt.c
@@ -0,0 +1,47 @@
+#include "src/main/c/Calculator/calculator.h"
+#include "/var/lib/gems/3.0.0/gems/ceedling-0.31.1/vendor/unity/src/unity.h"
+
+
+
+
+
+
+void setUp(void){
+
+
+
+}
+
+void tearDown(void){
+
+}
+
+
+
+
+
+void test_sqrt(void){
+
+
+
+    double result;
+
+    double a = 25;
+
+
+
+
+
+    result = sqrt(25);
+
+
+
+
+
+    UnityAssertEqualNumber((UNITY_INT)((5)), (UNITY_INT)((result)), (
+
+   ((void *)0)
+
+   ), (UNITY_UINT)(22), UNITY_DISPLAY_STYLE_INT);
+
+}
diff --git a/build/test/dependencies/test_sqrt.d b/build/test/dependencies/test_sqrt.d
new file mode 100644
index 0000000..dd1c1a5
--- /dev/null
+++ b/build/test/dependencies/test_sqrt.d
@@ -0,0 +1,4 @@
+build/test/out/c/test_sqrt.o: test/Calculator/test_sqrt.c \
+ /var/lib/gems/3.0.0/gems/ceedling-0.31.1/vendor/unity/src/unity.h \
+ /var/lib/gems/3.0.0/gems/ceedling-0.31.1/vendor/unity/src/unity_internals.h \
+ src/main/c/Calculator/calculator.h
diff --git a/build/test/dependencies/test_sqrt_runner.d b/build/test/dependencies/test_sqrt_runner.d
new file mode 100644
index 0000000..03a1b1d
--- /dev/null
+++ b/build/test/dependencies/test_sqrt_runner.d
@@ -0,0 +1,4 @@
+build/test/out/c/test_sqrt_runner.o: \
+ build/test/runners/test_sqrt_runner.c \
+ /var/lib/gems/3.0.0/gems/ceedling-0.31.1/vendor/unity/src/unity.h \
+ /var/lib/gems/3.0.0/gems/ceedling-0.31.1/vendor/unity/src/unity_internals.h
diff --git a/build/test/out/c/calculator.o b/build/test/out/c/calculator.o
index a125ff4..fe6dc14 100644
Binary files a/build/test/out/c/calculator.o and b/build/test/out/c/calculator.o differ
diff --git a/build/test/out/c/test_sqrt.o b/build/test/out/c/test_sqrt.o
new file mode 100644
index 0000000..04d17ed
Binary files /dev/null and b/build/test/out/c/test_sqrt.o differ
diff --git a/build/test/out/c/test_sqrt_runner.o b/build/test/out/c/test_sqrt_runner.o
new file mode 100644
index 0000000..6a1bce8
Binary files /dev/null and b/build/test/out/c/test_sqrt_runner.o differ
diff --git a/build/test/out/test_factorial.out b/build/test/out/test_factorial.out
index 2c6920e..ca8671c 100755
Binary files a/build/test/out/test_factorial.out and b/build/test/out/test_factorial.out differ
diff --git a/build/test/out/test_log.out b/build/test/out/test_log.out
index 537fdff..aa8b46f 100755
Binary files a/build/test/out/test_log.out and b/build/test/out/test_log.out differ
diff --git a/build/test/out/test_mod.out b/build/test/out/test_mod.out
index d525312..9d2af7c 100755
Binary files a/build/test/out/test_mod.out and b/build/test/out/test_mod.out differ
diff --git a/build/test/out/test_pow.out b/build/test/out/test_pow.out
index 6dffc28..5e6864d 100755
Binary files a/build/test/out/test_pow.out and b/build/test/out/test_pow.out differ
diff --git a/build/test/out/test_sqrt.out b/build/test/out/test_sqrt.out
new file mode 100755
index 0000000..c404a3f
Binary files /dev/null and b/build/test/out/test_sqrt.out differ
diff --git a/build/test/preprocess/files/test_sqrt.c b/build/test/preprocess/files/test_sqrt.c
new file mode 100644
index 0000000..2fc2a2d
--- /dev/null
+++ b/build/test/preprocess/files/test_sqrt.c
@@ -0,0 +1,47 @@
+#include "src/main/c/Calculator/calculator.h"
+#include "/var/lib/gems/3.0.0/gems/ceedling-0.31.1/vendor/unity/src/unity.h"
+
+
+
+
+
+
+void setUp(void){
+
+
+
+}
+
+void tearDown(void){
+
+}
+
+
+
+
+
+void test_sqrt(void){
+
+
+
+    double result;
+
+    double a = 25;
+
+
+
+
+
+    result = sqrt(25);
+
+
+
+
+
+    UnityAssertEqualNumber((UNITY_INT)((5)), (UNITY_INT)((result)), (
+
+   ((void *)0)
+
+   ), (UNITY_UINT)(22), UNITY_DISPLAY_STYLE_INT);
+
+}
diff --git a/build/test/preprocess/includes/test_sqrt.c b/build/test/preprocess/includes/test_sqrt.c
new file mode 100644
index 0000000..f2efae7
--- /dev/null
+++ b/build/test/preprocess/includes/test_sqrt.c
@@ -0,0 +1,3 @@
+---
+- "/var/lib/gems/3.0.0/gems/ceedling-0.31.1/vendor/unity/src/unity.h"
+- src/main/c/Calculator/calculator.h
diff --git a/build/test/results/test_factorial.pass b/build/test/results/test_factorial.pass
index 05c31d3..b8fed6d 100644
--- a/build/test/results/test_factorial.pass
+++ b/build/test/results/test_factorial.pass
@@ -15,4 +15,4 @@
   :failed: 0
   :ignored: 0
 :stdout: []
-:time: 0.004361564002465457
+:time: 0.006785353005398065
diff --git a/build/test/results/test_log.pass b/build/test/results/test_log.pass
index dbc8bdc..e671b6e 100644
--- a/build/test/results/test_log.pass
+++ b/build/test/results/test_log.pass
@@ -15,4 +15,4 @@
   :failed: 0
   :ignored: 0
 :stdout: []
-:time: 0.0030175010033417493
+:time: 0.006155624985694885
diff --git a/build/test/results/test_mod.pass b/build/test/results/test_mod.pass
index 5a1e2e8..1a37ad5 100644
--- a/build/test/results/test_mod.pass
+++ b/build/test/results/test_mod.pass
@@ -15,4 +15,4 @@
   :failed: 0
   :ignored: 0
 :stdout: []
-:time: 0.0026945919962599874
+:time: 0.006076960009522736
diff --git a/build/test/results/test_pow.pass b/build/test/results/test_pow.pass
index c0d42b3..38c87d4 100644
--- a/build/test/results/test_pow.pass
+++ b/build/test/results/test_pow.pass
@@ -19,4 +19,4 @@
   :failed: 0
   :ignored: 0
 :stdout: []
-:time: 0.0063727759988978505
+:time: 0.006162547011626884
diff --git a/build/test/results/test_sqrt.pass b/build/test/results/test_sqrt.pass
new file mode 100644
index 0000000..241978f
--- /dev/null
+++ b/build/test/results/test_sqrt.pass
@@ -0,0 +1,18 @@
+---
+:source:
+  :path: test/Calculator
+  :file: test_sqrt.c
+:successes:
+- :test: test_sqrt
+  :line: 13
+  :message: ''
+  :unity_test_time: 0
+:failures: []
+:ignores: []
+:counts:
+  :total: 1
+  :passed: 1
+  :failed: 0
+  :ignored: 0
+:stdout: []
+:time: 0.0060438819928094745
diff --git a/build/test/runners/test_sqrt_runner.c b/build/test/runners/test_sqrt_runner.c
new file mode 100644
index 0000000..54b130d
--- /dev/null
+++ b/build/test/runners/test_sqrt_runner.c
@@ -0,0 +1,81 @@
+/* AUTOGENERATED FILE. DO NOT EDIT. */
+
+/*=======Automagically Detected Files To Include=====*/
+#include "unity.h"
+
+int GlobalExpectCount;
+int GlobalVerifyOrder;
+char* GlobalOrderError;
+
+/*=======External Functions This Runner Calls=====*/
+extern void setUp(void);
+extern void tearDown(void);
+extern void test_sqrt(void);
+
+
+/*=======Mock Management=====*/
+static void CMock_Init(void)
+{
+  GlobalExpectCount = 0;
+  GlobalVerifyOrder = 0;
+  GlobalOrderError = NULL;
+}
+static void CMock_Verify(void)
+{
+}
+static void CMock_Destroy(void)
+{
+}
+
+/*=======Test Reset Options=====*/
+void resetTest(void);
+void resetTest(void)
+{
+  tearDown();
+  CMock_Verify();
+  CMock_Destroy();
+  CMock_Init();
+  setUp();
+}
+void verifyTest(void);
+void verifyTest(void)
+{
+  CMock_Verify();
+}
+
+/*=======Test Runner Used To Run Each Test=====*/
+static void run_test(UnityTestFunction func, const char* name, UNITY_LINE_TYPE line_num)
+{
+    Unity.CurrentTestName = name;
+    Unity.CurrentTestLineNumber = line_num;
+#ifdef UNITY_USE_COMMAND_LINE_ARGS
+    if (!UnityTestMatches())
+        return;
+#endif
+    Unity.NumberOfTests++;
+    UNITY_CLR_DETAILS();
+    UNITY_EXEC_TIME_START();
+    CMock_Init();
+    if (TEST_PROTECT())
+    {
+        setUp();
+        func();
+    }
+    if (TEST_PROTECT())
+    {
+        tearDown();
+        CMock_Verify();
+    }
+    CMock_Destroy();
+    UNITY_EXEC_TIME_STOP();
+    UnityConcludeTest();
+}
+
+/*=======MAIN=====*/
+int main(void)
+{
+  UnityBegin("test_sqrt.c");
+  run_test(test_sqrt, "test_sqrt", 13);
+
+  return UnityEnd();
+}
diff --git a/src/main/c/Calculator/calculator.c b/src/main/c/Calculator/calculator.c
index 27984a6..55a8841 100644
--- a/src/main/c/Calculator/calculator.c
+++ b/src/main/c/Calculator/calculator.c
@@ -14,6 +14,9 @@ double combination(int n, int r);
 double pow(double num1, double num2);
 int    mod(int num1,int num2);
 double log(num1);
+double sqrt(num1);
+
+
     int calculator() {
     int choice;
     double num1, num2, result;
@@ -93,7 +96,7 @@ double log(num1);
         case 8:
             return pow(num1, num2);    
         case 9:
-            return 0;// sqrt(num1);
+            return 0; sqrt(num1);
         case 10:
             return num1 * num1;
         case 11:
@@ -166,3 +169,7 @@ double log(double num1){
     double result = num1;
     return result;
 } 
+double sqrt(double num1){
+    double result = num1;
+    return result;  
+}
diff --git a/src/main/c/Calculator/calculator.h b/src/main/c/Calculator/calculator.h
index d86c05d..8c16e13 100644
--- a/src/main/c/Calculator/calculator.h
+++ b/src/main/c/Calculator/calculator.h
@@ -6,5 +6,6 @@ double pow(double num1, double num2);
 double factorial(double num);
 int mod(int num1, int num2);
 double log(double num1);
+double sqrt(double num1);
 
 #endif
diff --git a/test/Calculator/test_sqrt.c b/test/Calculator/test_sqrt.c
new file mode 100644
index 0000000..f89126c
--- /dev/null
+++ b/test/Calculator/test_sqrt.c
@@ -0,0 +1,25 @@
+#ifdef TEST
+#include "unity.h"
+#include "calculator.h"
+
+
+void setUp(void){
+    //Wenn Funktion Vorraussetzungen braucht
+}
+void tearDown(void){
+}
+
+
+void test_sqrt(void){
+    /* arrange */
+    double result;
+    double a = 25;
+
+    /* act */
+    result = sqrt(25);
+
+    /* assert */
+    TEST_ASSERT_EQUAL_INT(5, result);// sqrt(25) = 5
+}
+
+#endif // TEST