diff --git a/plugins/flutter/CHANGELOG.md b/plugins/flutter/CHANGELOG.md
index e081d019..f09177bd 100644
--- a/plugins/flutter/CHANGELOG.md
+++ b/plugins/flutter/CHANGELOG.md
@@ -17,7 +17,9 @@ The initial version. Hello, world!
 + Fix a bug about comment and indentation
 + Fix a bug about compile error line number
 
-## 0.4.8+4
+## 0.4.8+5
 
 + Downgrade to `sdk>=2.17.0`
-+ Fix some bugs about compile error
\ No newline at end of file
++ Fix some bugs about compile error
++ Fix a bug for jsonify `nan` or `inf`
++ Add `math.isnan` and `math.isinf`
\ No newline at end of file
diff --git a/plugins/flutter/pubspec.yaml b/plugins/flutter/pubspec.yaml
index b48f1233..cd828f07 100644
--- a/plugins/flutter/pubspec.yaml
+++ b/plugins/flutter/pubspec.yaml
@@ -1,6 +1,6 @@
 name: pocketpy
 description: A lightweight Python interpreter for game engines.
-version: 0.4.8+4
+version: 0.4.8+5
 homepage: https://pocketpy.dev
 repository: https://github.com/blueloveth/pocketpy
 
diff --git a/plugins/flutter/src/pocketpy.h b/plugins/flutter/src/pocketpy.h
index 7c223451..cd5eec97 100644
--- a/plugins/flutter/src/pocketpy.h
+++ b/plugins/flutter/src/pocketpy.h
@@ -6481,7 +6481,11 @@ void __initializeBuiltinFunctions(VM* _vm) {
     });
 
     _vm->bindMethod("float", "__json__", [](VM* vm, const pkpy::ArgList& args) {
-        return vm->PyStr(std::to_string((float)vm->PyFloat_AS_C(args[0])));
+        _Float val = vm->PyFloat_AS_C(args[0]);
+        if(std::isinf(val) || std::isnan(val)){
+            vm->valueError("cannot jsonify 'nan' or 'inf'");
+        }
+        return vm->PyStr(std::to_string(val));
     });
 
     /************ PyString ************/
@@ -6887,6 +6891,16 @@ void __addModuleMath(VM* vm){
         _Float b = vm->numToFloat(args[1]);
         return vm->PyBool(fabs(a - b) < 1e-9);
     });
+
+    vm->bindFunc(mod, "isnan", [](VM* vm, const pkpy::ArgList& args) {
+        vm->__checkArgSize(args, 1);
+        return vm->PyBool(std::isnan(vm->numToFloat(args[0])));
+    });
+
+    vm->bindFunc(mod, "isinf", [](VM* vm, const pkpy::ArgList& args) {
+        vm->__checkArgSize(args, 1);
+        return vm->PyBool(std::isinf(vm->numToFloat(args[0])));
+    });
 }
 
 class _PkExported{
diff --git a/plugins/godot/godot-cpp b/plugins/godot/godot-cpp
index c645191b..b1d3e4f6 160000
--- a/plugins/godot/godot-cpp
+++ b/plugins/godot/godot-cpp
@@ -1 +1 @@
-Subproject commit c645191b67d056996ee4d0d6a387758c16edf7e2
+Subproject commit b1d3e4f63e539272d5b77bfb44ed8f5778efef9e
diff --git a/plugins/unity/com.bl.pocketpy/Plugins/iOS/pocketpy.h b/plugins/unity/com.bl.pocketpy/Plugins/iOS/pocketpy.h
index 7c223451..cd5eec97 100644
--- a/plugins/unity/com.bl.pocketpy/Plugins/iOS/pocketpy.h
+++ b/plugins/unity/com.bl.pocketpy/Plugins/iOS/pocketpy.h
@@ -6481,7 +6481,11 @@ void __initializeBuiltinFunctions(VM* _vm) {
     });
 
     _vm->bindMethod("float", "__json__", [](VM* vm, const pkpy::ArgList& args) {
-        return vm->PyStr(std::to_string((float)vm->PyFloat_AS_C(args[0])));
+        _Float val = vm->PyFloat_AS_C(args[0]);
+        if(std::isinf(val) || std::isnan(val)){
+            vm->valueError("cannot jsonify 'nan' or 'inf'");
+        }
+        return vm->PyStr(std::to_string(val));
     });
 
     /************ PyString ************/
@@ -6887,6 +6891,16 @@ void __addModuleMath(VM* vm){
         _Float b = vm->numToFloat(args[1]);
         return vm->PyBool(fabs(a - b) < 1e-9);
     });
+
+    vm->bindFunc(mod, "isnan", [](VM* vm, const pkpy::ArgList& args) {
+        vm->__checkArgSize(args, 1);
+        return vm->PyBool(std::isnan(vm->numToFloat(args[0])));
+    });
+
+    vm->bindFunc(mod, "isinf", [](VM* vm, const pkpy::ArgList& args) {
+        vm->__checkArgSize(args, 1);
+        return vm->PyBool(std::isinf(vm->numToFloat(args[0])));
+    });
 }
 
 class _PkExported{
diff --git a/src/pocketpy.h b/src/pocketpy.h
index 6361f7cc..ded93e16 100644
--- a/src/pocketpy.h
+++ b/src/pocketpy.h
@@ -280,7 +280,11 @@ void __initializeBuiltinFunctions(VM* _vm) {
     });
 
     _vm->bindMethod("float", "__json__", [](VM* vm, const pkpy::ArgList& args) {
-        return vm->PyStr(std::to_string((float)vm->PyFloat_AS_C(args[0])));
+        _Float val = vm->PyFloat_AS_C(args[0]);
+        if(std::isinf(val) || std::isnan(val)){
+            vm->valueError("cannot jsonify 'nan' or 'inf'");
+        }
+        return vm->PyStr(std::to_string(val));
     });
 
     /************ PyString ************/
@@ -688,6 +692,16 @@ void __addModuleMath(VM* vm){
         _Float b = vm->numToFloat(args[1]);
         return vm->PyBool(fabs(a - b) < 1e-9);
     });
+
+    vm->bindFunc(mod, "isnan", [](VM* vm, const pkpy::ArgList& args) {
+        vm->__checkArgSize(args, 1);
+        return vm->PyBool(std::isnan(vm->numToFloat(args[0])));
+    });
+
+    vm->bindFunc(mod, "isinf", [](VM* vm, const pkpy::ArgList& args) {
+        vm->__checkArgSize(args, 1);
+        return vm->PyBool(std::isinf(vm->numToFloat(args[0])));
+    });
 }
 
 class _PkExported{
diff --git a/tests/_math.py b/tests/_math.py
index d43f9761..b10dd8da 100644
--- a/tests/_math.py
+++ b/tests/_math.py
@@ -1,4 +1,4 @@
-from math import log, log10, log2, sin, cos, tan, e, pi, isclose
+from math import log, log10, log2, sin, cos, tan, e, pi, isclose, isnan, isinf
 
 assert isclose(e, 2.718281828459045)
 assert isclose(pi, 3.141592653589793)
@@ -8,3 +8,9 @@ assert isclose(log2(10), 3.321928094887362)
 assert isclose(sin(0), 0.0)
 assert isclose(cos(0), 1.0)
 assert isclose(tan(0), 0.0)
+
+a = -0.1
+a = a**a
+assert isnan(a)
+assert not isinf(a)
+assert isinf(float("inf"))
\ No newline at end of file