diff --git a/Calc.swift b/Calc.swift
index e8005a3..4040077 100644
--- a/Calc.swift
+++ b/Calc.swift
@@ -1,8 +1,29 @@
-//
 //  Calc.swift
 //  bignumcalc
+//  2025-03-31
 //
-//  Created by Isaac Greene on 2025-03-31.
+// The author disclaims copyright to this source code. In place of
+// a legal notice, here is a blessing:
+//
+//    May you do good and not evil.
+//    May you find forgiveness for yourself and forgive others.
+//    May you share freely, never taking more than you give.
 //
 
 import Foundation
+var a: Double
+var b: Double
+var operation: String
+
+print("Enter first number: ")
+a = Double(readLine() ?? "") ?? 0
+
+print("Enter operation (+, -, *, /): ")
+operation = readLine() ?? ""
+
+print("Enter second number: ")
+b = Double(readLine() ?? "") ?? 0
+
+switch operation {
+    
+}
diff --git a/bignumcalc.xcodeproj/project.pbxproj b/bignumcalc.xcodeproj/project.pbxproj
index a1acaac..23a63b4 100644
--- a/bignumcalc.xcodeproj/project.pbxproj
+++ b/bignumcalc.xcodeproj/project.pbxproj
@@ -6,10 +6,15 @@
 	objectVersion = 77;
 	objects = {
 
+/* Begin PBXFileReference section */
+		6A4665922D9B96F8002F8AE1 /* Calc.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Calc.swift; sourceTree = "<group>"; };
+/* End PBXFileReference section */
+
 /* Begin PBXGroup section */
 		6A46658B2D9B96E2002F8AE1 = {
 			isa = PBXGroup;
 			children = (
+				6A4665922D9B96F8002F8AE1 /* Calc.swift */,
 			);
 			sourceTree = "<group>";
 		};