update

app/Http/Controllers/api/Home.php

@@ -152,6 +152,16 @@ class Home extends Controller
         }
         echo " = " . $sum;
         echo "<br/>";
+        $sum = 0;
+        for ($i = 3; $i < 20; $i = $i + 3) {
+            echo $matchingNumbers[$i];
+            $sum += $matchingNumbers[$i];
+            if ($i < 19) {
+                echo " + ";
+            }
+        }
+        echo " = " . $sum;
+        echo "<br/>";
 
         exit();