diff --git a/kalk/src/kalk_num/mod.rs b/kalk/src/kalk_num/mod.rs
index f875fd8..877ea5c 100644
--- a/kalk/src/kalk_num/mod.rs
+++ b/kalk/src/kalk_num/mod.rs
@@ -884,7 +884,7 @@ mod tests {
             (0.000000001, -1.0, "10^-9 - i ≈ -i"),
             (10e-17, 1.0, "i"),
             (1.0, 10e-17, "1"),
-            (10e-15, 0.0, "0"),
+            (10e-16, 0.0, "0"),
             (3.00000000004, 0.0, "3"),
         ];
         for (real, imaginary, output) in in_out {