diff --git a/poincare/test/approximation.cpp b/poincare/test/approximation.cpp
index bf8ff4a3e..d6573c8d7 100644
--- a/poincare/test/approximation.cpp
+++ b/poincare/test/approximation.cpp
@@ -269,12 +269,18 @@ QUIZ_CASE(poincare_approximation_function) {
 
   assert_expression_approximates_to<float>("gcd(234,394)", "2");
   assert_expression_approximates_to<double>("gcd(234,394)", "2");
+  assert_expression_approximates_to<float>("gcd(-234,394)", "2");
+  assert_expression_approximates_to<double>("gcd(234,-394)", "2");
+  assert_expression_approximates_to<float>("gcd(-234,-394)", "2");
 
   assert_expression_approximates_to<float>("im(2+3𝐢)", "3");
   assert_expression_approximates_to<double>("im(2+3𝐢)", "3");
 
   assert_expression_approximates_to<float>("lcm(234,394)", "46098");
   assert_expression_approximates_to<double>("lcm(234,394)", "46098");
+  assert_expression_approximates_to<float>("lcm(-234,394)", "46098");
+  assert_expression_approximates_to<double>("lcm(234,-394)", "46098");
+  assert_expression_approximates_to<float>("lcm(-234,-394)", "46098");
 
   assert_expression_approximates_to<float>("int(x,x, 1, 2)", "1.5");
   assert_expression_approximates_to<double>("int(x,x, 1, 2)", "1.5");