diff --git a/petabtests/cases/v2.0.0/math/math_tests.yaml b/petabtests/cases/v2.0.0/math/math_tests.yaml
index 27fc20d..8222852 100644
--- a/petabtests/cases/v2.0.0/math/math_tests.yaml
+++ b/petabtests/cases/v2.0.0/math/math_tests.yaml
@@ -185,3 +185,5 @@ cases:
   expected: 0.0
 - expression: a * b
   expected: a * b
+- expression: "!1"
+  expected: 0.0