diff --git a/exec/cnex/exclude.txt b/exec/cnex/exclude.txt
index 63e20f08c..e254dbbb7 100644
--- a/exec/cnex/exclude.txt
+++ b/exec/cnex/exclude.txt
@@ -6,7 +6,6 @@ gc1.neon                   # Object Count
 gc2.neon                   # Object Count
 gc3.neon                   # Object Count
 gc-two-pointers.neon       # garbage collection
-math-test.neon             # math.powmod()
 
 extsample-test.neon        # cell_set_pointer
 http-test.neon             # string$split
diff --git a/exec/cnex/number.c b/exec/cnex/number.c
index 858028d93..b66603657 100644
--- a/exec/cnex/number.c
+++ b/exec/cnex/number.c
@@ -328,6 +328,9 @@ Number number_abs(Number x)
 
 Number number_sign(Number x)
 {
+    if (bid128_isZero(x)) {
+        return bid128_from_uint32(0);
+    }
     return bid128_copySign(bid128_from_uint32(1), x);
 }