Update UnitTests.cs

Author: WBryant05

Tests/UnitTests.cs

@@ -9,7 +9,7 @@ public class Math
         [Test]
         public void Add_Valid()
         {
-            Assert.AreEqual(1, Program.Add("1", "2"));
+            Assert.AreEqual(3, Program.Add("1", "2"));
             Assert.AreEqual(5, Program.Add("3", "2"));
             Assert.AreEqual(12, Program.Add("5", "7"));
         }