diff --git a/main.c b/main.c
index 20ee8684b383ba13782bb3c56d7565e056bab78f..eafafb5e2263e99c119a8a290f3e79a44ec31a83 100644
--- a/main.c
+++ b/main.c
@@ -105,14 +105,21 @@ void problem_3() {
 /**
  * Problem 4
  *
- *
+ * Declare a double of "9999999.3399999999".
+ * Print to console.
+ * Cast to float and print again.
  */
 void problem_4() {
     printf("\n\nProblem 4 start.\n\n");
     printf("Expected Output:\n");
-    printf("\n");
+    printf("9999999.3399999999\n");
     printf("Actual Output:\n");
 
+    double test_double = 9999999.3399999999;
+    printf("%.10f\n", test_double);
+    float test_float = (float) test_double;
+    printf("%.10lf\n", test_float);
+
     printf("\nProblem 4 end.\n");
 }