diff --git a/src/Engine.php b/src/Engine.php
index d138dae..52c105e 100644
--- a/src/Engine.php
+++ b/src/Engine.php
@@ -10,7 +10,7 @@
 const MIN_NUM = 1;
 const MAX_NUM = 100;
 
-function communication(array $answers, $game): void
+function communication(array $answers, string $game): void
 {
     $name = greeting();
     line("$game");
diff --git a/src/Games/Calc.php b/src/Games/Calc.php
index fd2fe1e..5356aca 100644
--- a/src/Games/Calc.php
+++ b/src/Games/Calc.php
@@ -21,17 +21,14 @@ function calc(): void
     }
     communication($answers, $game);
 }
-function calculate($num1, $num2, $operation)
+function calculate(int $num1, int $num2, string $operation)
 {
     switch ($operation) {
         case '+':
             return $num1 + $num2;
-            break;
         case '-':
             return $num1 - $num2;
-            break;
         case '*':
             return $num1 * $num2;
-            break;
     }
 }
diff --git a/src/Games/Even.php b/src/Games/Even.php
index de7535f..bff4889 100644
--- a/src/Games/Even.php
+++ b/src/Games/Even.php
@@ -19,7 +19,7 @@ function even(): void
     communication($answers, $game);
 }
 
-function isEven($num): bool
+function isEven(int $num): bool
 {
     return $num % 2 === 0;
 }
diff --git a/src/Games/GCD.php b/src/Games/GCD.php
index dfed50b..cf30127 100644
--- a/src/Games/GCD.php
+++ b/src/Games/GCD.php
@@ -20,7 +20,7 @@ function gcd(): void
     communication($answers, $game);
 }
 
-function nod($x, $y)
+function nod(int $x, int $y)
 {
     while ($x != 0 && $y != 0) {
         if ($x >= $y) {