diff --git a/src/subtraction/.gitkeep b/src/subtraction/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/src/subtraction/subtraction.c b/src/subtraction/subtraction.c
new file mode 100644
index 0000000..f853998
--- /dev/null
+++ b/src/subtraction/subtraction.c
@@ -0,0 +1,6 @@
+#include "subtraction.h"
+int subtract(int a, int b) {
+    if (a==0) return b;
+    if(b==0) return a;
+    else return a - b;
+}
diff --git a/src/subtraction/subtraction.h b/src/subtraction/subtraction.h
new file mode 100644
index 0000000..0ae67d9
--- /dev/null
+++ b/src/subtraction/subtraction.h
@@ -0,0 +1,8 @@
+#ifndef subtraction_H
+#define subtraction_H
+
+int subtract(int a, int b);
+
+#endif
+
+
diff --git a/test/subtraction/.gitkeep b/test/subtraction/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/test/subtraction/subtraction.c b/test/subtraction/subtraction.c
new file mode 100644
index 0000000..d49be5c
--- /dev/null
+++ b/test/subtraction/subtraction.c
@@ -0,0 +1,11 @@
+#include "unity.h"
+#include "subtraction.h"
+void setUp(){}
+
+void tearDown(){}
+
+void test_subtraction() {
+    TEST_ASSERT_EQUAL_INT(1, subtract(3, 2));
+    TEST_ASSERT_EQUAL_INT(5, subtract(2, -3));
+    TEST_ASSERT_EQUAL_INT(0, subtract(0, 0));
+}