diff --git a/src/addition.c b/src/addition.c
index 192513a..753d77d 100644
--- a/src/addition.c
+++ b/src/addition.c
@@ -2,5 +2,5 @@
 #include <stdlib.h>
 
 void full_adder (int* sum, int* nextcarry, int number1, int number2, int carry) {
-    sum[0] = carry;
+    sum[0] = number1 ^ number2 ^ carry;
 }
\ No newline at end of file