diff --git a/src/NXP/Classes/Token/TokenMinus.php b/src/NXP/Classes/Token/TokenMinus.php
index d8ac079..b4b04e3 100644
--- a/src/NXP/Classes/Token/TokenMinus.php
+++ b/src/NXP/Classes/Token/TokenMinus.php
@@ -53,8 +53,12 @@ class TokenMinus extends AbstractOperator
         $op2 = array_pop($stack);
         $op1 = array_pop($stack);
 
-        if ($op1 === null || $op2 === null) {
-            throw new IncorrectExpressionException("Subtraction requires two operators");
+        if ($op2 === null) {
+            throw new IncorrectExpressionException("Subtraction requires right operator");
+        }
+
+        if (!$op1) {
+            $op1 = new TokenNumber(0);
         }
 
         $result = $op1->getValue() - $op2->getValue();
diff --git a/tests/MathTest.php b/tests/MathTest.php
index 27817db..3e5a7ff 100644
--- a/tests/MathTest.php
+++ b/tests/MathTest.php
@@ -297,4 +297,11 @@ class MathTest extends \PHPUnit\Framework\TestCase
         $calculator->execute('test("' . $testString . '")'); // single quotes
         $calculator->execute("test('" . $testString . "')"); // double quotes
     }
+
+    public function testBeginWithBracketAndMinus()
+    {
+        $calculator = new MathExecutor();
+        $this->assertEquals(-4, $calculator->execute('(-4)'));
+        $this->assertEquals(1, $calculator->execute('(-4 + 5)'));
+    }
 }