diff --git a/ext/equations-parser b/ext/equations-parser
index 7428a00..ec64e60 160000
--- a/ext/equations-parser
+++ b/ext/equations-parser
@@ -1 +1 @@
-Subproject commit 7428a00a7e56f14afc9178de599e331bae71d17b
+Subproject commit ec64e60b8cd11299c2237b13630801f79a1954c1
diff --git a/ext/libnativemath/extconf.rb b/ext/libnativemath/extconf.rb
index b0973e1..e43b45c 100644
--- a/ext/libnativemath/extconf.rb
+++ b/ext/libnativemath/extconf.rb
@@ -38,7 +38,7 @@
 end
 
 GIT_REPOSITORY = 'https://github.com/oxeanbits/equations-parser.git'.freeze
-COMMIT = '7428a00a7e56f14afc9178de599e331bae71d17b'.freeze
+COMMIT = 'ec64e60b8cd11299c2237b13630801f79a1954c1'.freeze
 
 Dir.chdir(BASEDIR) do
   system('git init')
diff --git a/test/test_parsec.rb b/test/test_parsec.rb
index 3c337c5..a839351 100644
--- a/test/test_parsec.rb
+++ b/test/test_parsec.rb
@@ -38,6 +38,22 @@ def test_complex_math_equations
     assert_equal(4.56, parser.eval_equation('round_decimal(4.559, 2)'))
   end
 
+  def test_round_with_optional_direction
+    parser = Parsec::Parsec
+
+    assert_equal(10, parser.eval_equation('round(10.1)'))
+    assert_equal(11, parser.eval_equation('round(10.1, "up")'))
+    assert_equal(10, parser.eval_equation('round(10.9, "down")'))
+    assert_equal(-10, parser.eval_equation('round(-10.9, "up")'))
+    assert_equal(-11, parser.eval_equation('round(-10.1, "down")'))
+    
+    assert_equal(4.63, parser.eval_equation('round_decimal(4.621, 2, "up")'))
+    assert_equal(4.62, parser.eval_equation('round_decimal(4.629, 2, "down")'))
+
+    assert_raises(SyntaxError) { parser.eval_equation('round(10.5, "invalid")') }
+    assert_raises(SyntaxError) { parser.eval_equation('round(10.5, "up", "extra")') }
+  end
+
   def test_if_then_else_equations
     parser = Parsec::Parsec
     assert_equal('bigger', parser.eval_equation('4 > 2 ? "bigger" : "smaller"'))