diff --git a/stdlib/2and3/math.pyi b/stdlib/2and3/math.pyi
index aa8b191ae..7e2686c02 100644
--- a/stdlib/2and3/math.pyi
+++ b/stdlib/2and3/math.pyi
@@ -13,71 +13,71 @@ if sys.version_info >= (3, 5):
 if sys.version_info >= (3, 6):
     tau: float
 
-def acos(x: SupportsFloat) -> float: ...
-def acosh(x: SupportsFloat) -> float: ...
-def asin(x: SupportsFloat) -> float: ...
-def asinh(x: SupportsFloat) -> float: ...
-def atan(x: SupportsFloat) -> float: ...
-def atan2(y: SupportsFloat, x: SupportsFloat) -> float: ...
-def atanh(x: SupportsFloat) -> float: ...
+def acos(__x: SupportsFloat) -> float: ...
+def acosh(__x: SupportsFloat) -> float: ...
+def asin(__x: SupportsFloat) -> float: ...
+def asinh(__x: SupportsFloat) -> float: ...
+def atan(__x: SupportsFloat) -> float: ...
+def atan2(__y: SupportsFloat, __x: SupportsFloat) -> float: ...
+def atanh(__x: SupportsFloat) -> float: ...
 if sys.version_info >= (3,):
-    def ceil(x: SupportsFloat) -> int: ...
+    def ceil(__x: SupportsFloat) -> int: ...
 else:
-    def ceil(x: SupportsFloat) -> float: ...
-def copysign(x: SupportsFloat, y: SupportsFloat) -> float: ...
-def cos(x: SupportsFloat) -> float: ...
-def cosh(x: SupportsFloat) -> float: ...
-def degrees(x: SupportsFloat) -> float: ...
+    def ceil(__x: SupportsFloat) -> float: ...
+def copysign(__x: SupportsFloat, __y: SupportsFloat) -> float: ...
+def cos(__x: SupportsFloat) -> float: ...
+def cosh(__x: SupportsFloat) -> float: ...
+def degrees(__x: SupportsFloat) -> float: ...
 if sys.version_info >= (3, 8):
     def dist(__p: Iterable[SupportsFloat], __q: Iterable[SupportsFloat]) -> float: ...
-def erf(x: SupportsFloat) -> float: ...
-def erfc(x: SupportsFloat) -> float: ...
-def exp(x: SupportsFloat) -> float: ...
-def expm1(x: SupportsFloat) -> float: ...
-def fabs(x: SupportsFloat) -> float: ...
-def factorial(x: SupportsInt) -> int: ...
+def erf(__x: SupportsFloat) -> float: ...
+def erfc(__x: SupportsFloat) -> float: ...
+def exp(__x: SupportsFloat) -> float: ...
+def expm1(__x: SupportsFloat) -> float: ...
+def fabs(__x: SupportsFloat) -> float: ...
+def factorial(__x: SupportsInt) -> int: ...
 if sys.version_info >= (3,):
-    def floor(x: SupportsFloat) -> int: ...
+    def floor(__x: SupportsFloat) -> int: ...
 else:
-    def floor(x: SupportsFloat) -> float: ...
-def fmod(x: SupportsFloat, y: SupportsFloat) -> float: ...
-def frexp(x: SupportsFloat) -> Tuple[float, int]: ...
-def fsum(iterable: Iterable[float]) -> float: ...
-def gamma(x: SupportsFloat) -> float: ...
+    def floor(__x: SupportsFloat) -> float: ...
+def fmod(__x: SupportsFloat, __y: SupportsFloat) -> float: ...
+def frexp(__x: SupportsFloat) -> Tuple[float, int]: ...
+def fsum(__seq: Iterable[float]) -> float: ...
+def gamma(__x: SupportsFloat) -> float: ...
 if sys.version_info >= (3, 5):
-    def gcd(a: int, b: int) -> int: ...
+    def gcd(__x: int, __y: int) -> int: ...
 if sys.version_info >= (3, 8):
     def hypot(*coordinates: SupportsFloat) -> float: ...
 else:
     def hypot(__x: SupportsFloat, __y: SupportsFloat) -> float: ...
 if sys.version_info >= (3, 5):
-    def isclose(a: SupportsFloat, b: SupportsFloat, rel_tol: SupportsFloat = ..., abs_tol: SupportsFloat = ...) -> bool: ...
-def isinf(x: SupportsFloat) -> bool: ...
+    def isclose(a: SupportsFloat, b: SupportsFloat, *, rel_tol: SupportsFloat = ..., abs_tol: SupportsFloat = ...) -> bool: ...
+def isinf(__x: SupportsFloat) -> bool: ...
 if sys.version_info >= (3,):
-    def isfinite(x: SupportsFloat) -> bool: ...
-def isnan(x: SupportsFloat) -> bool: ...
+    def isfinite(__x: SupportsFloat) -> bool: ...
+def isnan(__x: SupportsFloat) -> bool: ...
 if sys.version_info >= (3, 8):
     def isqrt(__n: int) -> int: ...
-def ldexp(x: SupportsFloat, i: int) -> float: ...
-def lgamma(x: SupportsFloat) -> float: ...
+def ldexp(__x: SupportsFloat, __i: int) -> float: ...
+def lgamma(__x: SupportsFloat) -> float: ...
 def log(x: SupportsFloat, base: SupportsFloat = ...) -> float: ...
-def log10(x: SupportsFloat) -> float: ...
-def log1p(x: SupportsFloat) -> float: ...
+def log10(__x: SupportsFloat) -> float: ...
+def log1p(__x: SupportsFloat) -> float: ...
 if sys.version_info >= (3, 3):
-    def log2(x: SupportsFloat) -> float: ...
-def modf(x: SupportsFloat) -> Tuple[float, float]: ...
-def pow(x: SupportsFloat, y: SupportsFloat) -> float: ...
+    def log2(__x: SupportsFloat) -> float: ...
+def modf(__x: SupportsFloat) -> Tuple[float, float]: ...
+def pow(__x: SupportsFloat, __y: SupportsFloat) -> float: ...
 if sys.version_info >= (3, 8):
     @overload
     def prod(__iterable: Iterable[int], *, start: int = ...) -> int: ...  # type: ignore
     @overload
     def prod(__iterable: Iterable[SupportsFloat], *, start: SupportsFloat = ...) -> float: ...
-def radians(x: SupportsFloat) -> float: ...
+def radians(__x: SupportsFloat) -> float: ...
 if sys.version_info >= (3, 7):
-    def remainder(x: SupportsFloat, y: SupportsFloat) -> float: ...
-def sin(x: SupportsFloat) -> float: ...
-def sinh(x: SupportsFloat) -> float: ...
-def sqrt(x: SupportsFloat) -> float: ...
-def tan(x: SupportsFloat) -> float: ...
-def tanh(x: SupportsFloat) -> float: ...
-def trunc(x: SupportsFloat) -> int: ...
+    def remainder(__x: SupportsFloat, __y: SupportsFloat) -> float: ...
+def sin(__x: SupportsFloat) -> float: ...
+def sinh(__x: SupportsFloat) -> float: ...
+def sqrt(__x: SupportsFloat) -> float: ...
+def tan(__x: SupportsFloat) -> float: ...
+def tanh(__x: SupportsFloat) -> float: ...
+def trunc(__x: SupportsFloat) -> int: ...