diff --git a/src/main/c/BasicMode.h b/src/main/c/BasicMode.h
index 43a3522..cb621c8 100644
--- a/src/main/c/BasicMode.h
+++ b/src/main/c/BasicMode.h
@@ -5,6 +5,7 @@ long long int DecToBin(long long int n);
 long long int BinToDec(long long int n);
 long long int addition(long long int a, long long int b);
 long long int multiplication(long long int a, long long int b);
+long long int subtraction(long long int a, long long int b);