diff --git a/Cargo.toml b/Cargo.toml
index dc345c6..90fea3d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -78,7 +78,7 @@ num-traits = { version = "0.2.17", default-features = false }
 num-derive = { version = "0.4.1", default-features = false }
 bin-pool = { version = "0.1.1", default-features = false }
 rand = { version = "0.8.5", default-features = false }
-checked-float = { version = "0.1.4", default-features = false, features = ["serde"] }
+checked-float = { version = "0.1.5", default-features = false, features = ["serde"] }
 educe = { version = "0.4.23", default-features = false, features = ["Debug", "Clone", "Copy", "PartialOrd", "Ord", "PartialEq", "Eq", "Default"] }
 libm = { version = "0.2.8", default-features = false }
 monostate = { version = "0.1.9", default-features = false }
diff --git a/src/runtime.rs b/src/runtime.rs
index f347fa7..763e145 100644
--- a/src/runtime.rs
+++ b/src/runtime.rs
@@ -35,10 +35,10 @@ pub enum NumberError {
 pub struct NumberChecker;
 impl FloatChecker<f64> for NumberChecker {
     type Error = NumberError;
-    fn check(value: f64) -> Result<(), Self::Error> {
+    fn check(value: f64) -> Result<f64, Self::Error> {
         if value.is_nan() { return Err(NumberError::Nan); }
         if value.is_infinite() { return Err(NumberError::Infinity); }
-        Ok(())
+        Ok(if value.to_bits() == 0x8000000000000000 { 0.0 } else { value }) // we don't support signed zero - only useful in conjunction with infinity
     }
 }
 
@@ -699,7 +699,7 @@ impl SimpleValue {
     pub fn into_json<C: CustomTypes<S>, S: System<C>>(self) -> Result<Json, IntoJsonError<C, S>> {
         Ok(match self {
             SimpleValue::Bool(x) => Json::Bool(x),
-            SimpleValue::Number(x) => Json::Number(JsonNumber::from_f64(x.get()).unwrap()), // Number forbids NaN and Infinity, so this is infallible
+            SimpleValue::Number(x) => Json::Number(JsonNumber::from_f64(x.get()).unwrap()), // Json and Number forbid NaN and Infinity, so this is infallible
             SimpleValue::String(x) => Json::String(x),
             SimpleValue::List(x) => Json::Array(x.into_iter().map(SimpleValue::into_json).collect::<Result<_,_>>()?),
             SimpleValue::Image(_) => return Err(IntoJsonError::ComplexType(Type::Image)),
@@ -713,7 +713,7 @@ impl SimpleValue {
         Ok(match value {
             Json::Null => return Err(FromJsonError::Null),
             Json::Bool(x) => SimpleValue::Bool(x),
-            Json::Number(x) => SimpleValue::Number(Number::new(x.as_f64().unwrap()).unwrap()), // Json forbids NaN and Infinity, so this is infallible
+            Json::Number(x) => SimpleValue::Number(Number::new(x.as_f64().unwrap()).unwrap()), // Json and Number forbid NaN and Infinity, so this is infallible
             Json::String(x) => SimpleValue::String(x),
             Json::Array(x) => SimpleValue::List(x.into_iter().map(SimpleValue::from_json).collect::<Result<_,_>>()?),
             Json::Object(x) => SimpleValue::List(x.into_iter().map(|(k, v)| {
@@ -726,7 +726,7 @@ impl SimpleValue {
     pub fn into_netsblox_json(self) -> Json {
         match self {
             SimpleValue::Bool(x) => Json::Bool(x),
-            SimpleValue::Number(x) => Json::Number(JsonNumber::from_f64(x.get()).unwrap()), // Number forbids NaN and Infinity, so this is infallible
+            SimpleValue::Number(x) => Json::Number(JsonNumber::from_f64(x.get()).unwrap()), // Json and Number forbid NaN and Infinity, so this is infallible
             SimpleValue::String(x) => Json::String(x),
             SimpleValue::List(x) => Json::Array(x.into_iter().map(SimpleValue::into_netsblox_json).collect()),
             SimpleValue::Image(img) => {
@@ -741,7 +741,7 @@ impl SimpleValue {
         Ok(match value {
             Json::Null => return Err(FromNetsBloxJsonError::Null),
             Json::Bool(x) => SimpleValue::Bool(x),
-            Json::Number(x) => SimpleValue::Number(Number::new(x.as_f64().unwrap()).unwrap()), // Json forbids NaN and Infinity, so this is infallible
+            Json::Number(x) => SimpleValue::Number(Number::new(x.as_f64().unwrap()).unwrap()), // Json and Number forbid NaN and Infinity, so this is infallible
             Json::Array(x) => SimpleValue::List(x.into_iter().map(SimpleValue::from_netsblox_json).collect::<Result<_,_>>()?),
             Json::Object(x) => SimpleValue::List(x.into_iter().map(|(k, v)| {
                 Ok(SimpleValue::List(vec![SimpleValue::String(k), SimpleValue::from_netsblox_json(v)?]))
diff --git a/src/test/mod.rs b/src/test/mod.rs
index f639418..e564f44 100644
--- a/src/test/mod.rs
+++ b/src/test/mod.rs
@@ -92,7 +92,10 @@ fn assert_values_eq<'gc>(got: &Value<'gc, C, StdSystem<C>>, expected: &Value<'gc
         }
         (Value::Number(got), Value::Number(expected)) => {
             let (got, expected) = (got.get(), expected.get());
-            let good = if got.is_finite() && expected.is_finite() { (got - expected).abs() <= epsilon } else { got == expected };
+            let good = match epsilon <= 0.0 {
+                true => got.to_bits() == expected.to_bits(),
+                false => if got.is_finite() && expected.is_finite() { (got - expected).abs() <= epsilon } else { got == expected },
+            };
             if !good { panic!("{} - number error - got {} expected {}", path, got, expected) }
         }
         (Value::String(got), Value::String(expected)) => {
diff --git a/src/test/process.rs b/src/test/process.rs
index c4f4adb..f58c4e6 100644
--- a/src/test/process.rs
+++ b/src/test/process.rs
@@ -1708,16 +1708,16 @@ fn test_proc_signed_zero() {
 
     run_till_term(&mut env, |mc, _, res| {
         let expect = Value::from_simple(mc, SimpleValue::from_json(json!([
-            [0.0, -0.0, -0.0],
-            ["0", "-0", "-0"],
-            [false, true, true, false, true, false, false],
+            [0.0, 0.0, 0.0],
+            ["0", "0", "0"],
+            [false, true, true, false, true, false, true],
+            [false, true, true, false, true, false, true],
+            [false, true, true, false, true, false, true],
+            [false, true, true, false, true, false, true],
             [false, true, true, false, true, false, true],
-            [false, true, true, false, true, false, false],
-            [false, true, true, false, true, false, false],
             [false, true, true, false, true, false, true],
-            [false, true, true, false, true, false, false],
         ])).unwrap());
-        assert_values_eq(&res.unwrap().0, &expect, 1e-5, "signed zero");
+        assert_values_eq(&res.unwrap().0, &expect, 0.0, "signed zero");
     });
 }