diff --git a/src/machine/arithmetic_ops.rs b/src/machine/arithmetic_ops.rs
index dc06fd5a..4e3f832a 100644
--- a/src/machine/arithmetic_ops.rs
+++ b/src/machine/arithmetic_ops.rs
@@ -676,6 +676,10 @@ impl MachineState {
                 MachineError::type_error(self.heap.h(), ValidType::Integer, n2),
                 stub,
             )),
+            (Number::Fixnum(_), n2) => Err(self.error_form(
+                MachineError::type_error(self.heap.h(), ValidType::Integer, n2),
+                stub,
+            )),
             (n1, _) => Err(self.error_form(
                 MachineError::type_error(self.heap.h(), ValidType::Integer, n1),
                 stub,
@@ -716,6 +720,10 @@ impl MachineState {
                 MachineError::type_error(self.heap.h(), ValidType::Integer, n2),
                 stub,
             )),
+            (Number::Fixnum(_), n2) => Err(self.error_form(
+                MachineError::type_error(self.heap.h(), ValidType::Integer, n2),
+                stub,
+            )),
             (n1, _) => Err(self.error_form(
                 MachineError::type_error(self.heap.h(), ValidType::Integer, n1),
                 stub,