diff --git a/addition.py b/addition.py
index e184760..0531013 100644
--- a/addition.py
+++ b/addition.py
@@ -2,6 +2,6 @@
 num2 = int(input("Enter second number: "))
 
 # addition
-result = num1 * num2
+result = num1 + num2
 
 print("The sum of", num1, "and", num2, "is", result)
diff --git a/gcd.py b/gcd.py
index 3c39d8d..f66d895 100644
--- a/gcd.py
+++ b/gcd.py
@@ -1,7 +1,8 @@
+import math
 num1 = int(input("Enter first number: "))
 num2 = int(input("Enter second number: "))
 
 # greatest common divisor
-result = num1 + num2
+result = math.gcd(num1,num2)
 
 print("The GCD of", num1, "and", num2, "is", result)
diff --git a/simple_interest.py b/simple_interest.py
index 88d4325..ff86fa5 100644
--- a/simple_interest.py
+++ b/simple_interest.py
@@ -3,6 +3,6 @@
 time = float(input("Enter the number of years for the investment: "))
 
 # Simple Interest Calculation
-interest = (principal * rate * time)
+interest = (principal * rate * time)/100
 
 print("The simple interest for an investment of", principal, "at", rate, "% for", time, "years is:", interest)