Index: libcxx/include/CMakeLists.txt
===================================================================
--- libcxx/include/CMakeLists.txt
+++ libcxx/include/CMakeLists.txt
@@ -118,6 +118,7 @@
   mutex
   new
   numeric
+  numbers
   optional
   ostream
   queue
Index: libcxx/include/module.modulemap
===================================================================
--- libcxx/include/module.modulemap
+++ libcxx/include/module.modulemap
@@ -382,6 +382,10 @@
     header "numeric"
     export *
   }
+  module numbers {
+    header "numbers"
+    export *
+  }
   module optional {
     header "optional"
     export *
Index: libcxx/include/numbers
===================================================================
--- /dev/null
+++ libcxx/include/numbers
@@ -0,0 +1,181 @@
+// -*- C++ -*-
+//===---------------------------- numbers ---------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP_NUMBERS
+#define _LIBCPP_NUMBERS
+
+/*
+    numbers synopsis
+
+namespace std::numbers
+{
+  template<class T> inline constexpr T e_v          = unspecified;
+  template<class T> inline constexpr T log2e_v      = unspecified;
+  template<class T> inline constexpr T log10e_v     = unspecified;
+  template<class T> inline constexpr T pi_v         = unspecified;
+  template<class T> inline constexpr T inv_pi_v     = unspecified;
+  template<class T> inline constexpr T inv_sqrtpi_v = unspecified;
+  template<class T> inline constexpr T ln2_v        = unspecified;
+  template<class T> inline constexpr T ln10_v       = unspecified;
+  template<class T> inline constexpr T sqrt2_v      = unspecified;
+  template<class T> inline constexpr T sqrt3_v      = unspecified;
+  template<class T> inline constexpr T inv_sqrt3_v  = unspecified;
+  template<class T> inline constexpr T egamma_v     = unspecified;
+  template<class T> inline constexpr T phi_v        = unspecified;
+
+  template<floating_point T> inline constexpr T e_v<T>          = see below;
+  template<floating_point T> inline constexpr T log2e_v<T>      = see below;
+  template<floating_point T> inline constexpr T log10e_v<T>     = see below;
+  template<floating_point T> inline constexpr T pi_v<T>         = see below;
+  template<floating_point T> inline constexpr T inv_pi_v<T>     = see below;
+  template<floating_point T> inline constexpr T inv_sqrtpi_v<T> = see below;
+  template<floating_point T> inline constexpr T ln2_v<T>        = see below;
+  template<floating_point T> inline constexpr T ln10_v<T>       = see below;
+  template<floating_point T> inline constexpr T sqrt2_v<T>      = see below;
+  template<floating_point T> inline constexpr T sqrt3_v<T>      = see below;
+  template<floating_point T> inline constexpr T inv_sqrt3_v<T>  = see below;
+  template<floating_point T> inline constexpr T egamma_v<T>     = see below;
+  template<floating_point T> inline constexpr T phi_v<T>        = see below;
+
+  inline constexpr double e          = e_v<double>;
+  inline constexpr double log2e      = log2e_v<double>;
+  inline constexpr double log10e     = log10e_v<double>;
+  inline constexpr double pi         = pi_v<double>;
+  inline constexpr double inv_pi     = inv_pi_v<double>;
+  inline constexpr double inv_sqrtpi = inv_sqrtpi_v<double>;
+  inline constexpr double ln2        = ln2_v<double>;
+  inline constexpr double ln10       = ln10_v<double>;
+  inline constexpr double sqrt2      = sqrt2_v<double>;
+  inline constexpr double sqrt3      = sqrt3_v<double>;
+  inline constexpr double inv_sqrt3  = inv_sqrt3_v<double>;
+  inline constexpr double egamma     = egamma_v<double>;
+  inline constexpr double phi        = phi_v<double>;
+}  // std::numbers
+
+*/
+
+#include <__config>
+#include <type_traits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17
+
+namespace numbers {
+template<typename T>
+using _IsFloat = _EnableIf<is_floating_point_v<T>, T>;
+
+// e
+template<class T>
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+T e_v = _IsFloat<T>(2.718281828459045235360287471352663L);
+
+// log2(e)
+template<class T>
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+T log2e_v = _IsFloat<T>(1.442695040888963407359924681001892L);
+
+// log10(e)
+template<class T>
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+T log10e_v = _IsFloat<T>(0.4342944819032518276511289189166051L);
+
+// pi
+template<class T>
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+T pi_v = _IsFloat<T>(3.141592653589793238462643383279503L);
+
+// 1/pi
+template<class T>
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+T inv_pi_v = _IsFloat<T>(0.3183098861837906715377675267450287L);
+
+// 1/sqrt(pi)
+template<class T>
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+T inv_sqrtpi_v = _IsFloat<T>(0.5641895835477562869480794515607726L);
+
+// log_e(2)
+template<class T>
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+T ln2_v = _IsFloat<T>(0.6931471805599453094172321214581766L);
+
+// log_e(10)
+template<class T>
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+T ln10_v = _IsFloat<T>(2.302585092994045684017991454684364L);
+
+// sqrt(2)
+template<class T>
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+T sqrt2_v = _IsFloat<T>(1.414213562373095048801688724209698L);
+
+// sqrt(3)
+template<class T>
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+T sqrt3_v = _IsFloat<T>(1.732050807568877293527446341505872L);
+
+// 1/sqrt(3)
+template<class T>
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+T inv_sqrt3_v = _IsFloat<T>(0.5773502691896257645091487805019575L);
+
+// Euler-Mascheroni gama constant
+template<class T>
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+T egamma_v = _IsFloat<T>(0.5772156649015328606065120900824024L);
+
+// Golden ratio phi constant
+template<class T>
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+T phi_v = _IsFloat<T>(1.618033988749894848204586834365638L);
+
+
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+                   double e          = e_v<double>;
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+                   double log2e      = log2e_v<double>;
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+                   double log10e     = log10e_v<double>;
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+                   double pi         = pi_v<double>;
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+                   double inv_pi     = inv_pi_v<double>;
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+                   double inv_sqrtpi = inv_sqrtpi_v<double>;
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+                   double ln2        = ln2_v<double>;
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+                   double ln10       = ln10_v<double>;
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+                   double sqrt2      = sqrt2_v<double>;
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+                   double sqrt3      = sqrt3_v<double>;
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+                   double inv_sqrt3  = inv_sqrt3_v<double>;
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+                   double egamma     = egamma_v<double>;
+_LIBCPP_INLINE_VAR _LIBCPP_CONSTEXPR
+                   double phi        = phi_v<double>;
+} //namespace numbers
+
+#endif //_LIBCPP_STD_VER > 17
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif  //_LIBCPP_NUMBERS
Index: libcxx/test/libcxx/double_include.sh.cpp
===================================================================
--- libcxx/test/libcxx/double_include.sh.cpp
+++ libcxx/test/libcxx/double_include.sh.cpp
@@ -99,6 +99,7 @@
 #endif
 #include <new>
 #include <numeric>
+#include <numbers>
 #include <optional>
 #include <ostream>
 #include <queue>
Index: libcxx/test/std/numerics/numbers/numbers.pass.cpp
===================================================================
--- /dev/null
+++ libcxx/test/std/numerics/numbers/numbers.pass.cpp
@@ -0,0 +1,81 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
+
+
+#include <numbers>
+#include "test_macros.h"
+struct S1 {
+};
+
+int main() {
+
+  // float
+  constexpr float f   = std::numbers::e_v<float>;
+  constexpr float f1  = std::numbers::log2e_v<float>;
+  constexpr float f2  = std::numbers::log10e_v<float>;
+  constexpr float f3  = std::numbers::pi_v<float>;
+  constexpr float f4  = std::numbers::inv_pi_v<float>;
+  constexpr float f5  = std::numbers::inv_sqrtpi_v<float>;
+  constexpr float f6  = std::numbers::ln2_v<float>;
+  constexpr float f7  = std::numbers::ln10_v<float>;
+  constexpr float f8  = std::numbers::sqrt2_v<float>;
+  constexpr float f9  = std::numbers::sqrt3_v<float>;
+  constexpr float f10 = std::numbers::inv_sqrt3_v<float>;
+  constexpr float f11 = std::numbers::egamma_v<float>;
+  constexpr float f12 = std::numbers::phi_v<float>;
+
+  // double
+  constexpr double d   = std::numbers::e_v<double>;
+  constexpr double d1  = std::numbers::log2e_v<double>;
+  constexpr double d2  = std::numbers::log10e_v<double>;
+  constexpr double d3  = std::numbers::pi_v<double>;
+  constexpr double d4  = std::numbers::inv_pi_v<double>;
+  constexpr double d5  = std::numbers::inv_sqrtpi_v<double>;
+  constexpr double d6  = std::numbers::ln2_v<double>;
+  constexpr double d7  = std::numbers::ln10_v<double>;
+  constexpr double d8  = std::numbers::sqrt2_v<double>;
+  constexpr double d9  = std::numbers::sqrt3_v<double>;
+  constexpr double d10 = std::numbers::inv_sqrt3_v<double>;
+  constexpr double d11 = std::numbers::egamma_v<double>;
+  constexpr double d12 = std::numbers::phi_v<double>;
+  // static assert checks
+  static_assert(d == std::numbers::e, "d != std::numbers::e ");
+  static_assert(d1 == std::numbers::log2e, "d1 != std::numbers::log2e");
+  static_assert(d2 == std::numbers::log10e, "d2 != std::numbers::log10e");
+  static_assert(d3 == std::numbers::pi, "d3 != std::numbers::pi");
+  static_assert(d4 == std::numbers::inv_pi, "d4 != std::numbers::inv_pi");
+  static_assert(d5 == std::numbers::inv_sqrtpi, "d5 != std::numbers::inv_sqrtpi");
+  static_assert(d6 == std::numbers::ln2, "d6 != std::numbers::ln2");
+  static_assert(d7 == std::numbers::ln10, "d7 != std::numbers::ln10");
+  static_assert(d8 == std::numbers::sqrt2, "d8 != std::numbers::sqrt2");
+  static_assert(d9 == std::numbers::sqrt3, "d9 != std::numbers::sqrt3");
+  static_assert(d10 == std::numbers::inv_sqrt3, "d10 != std::numbers::inv_sqrt3");
+  static_assert(d11 == std::numbers::egamma, "d11 != std::numbers::egamma");
+  static_assert(d12 == std::numbers::phi, "d12 != std::numbers::phi");
+  // long oduble
+  constexpr long double ld   = std::numbers::e_v<long double>;
+  constexpr long double ld1  = std::numbers::log2e_v<long double>;
+  constexpr long double ld2  = std::numbers::log10e_v<long double>;
+  constexpr long double ld3  = std::numbers::pi_v<long double>;
+  constexpr long double ld4  = std::numbers::inv_pi_v<long double>;
+  constexpr long double ld5  = std::numbers::inv_sqrtpi_v<long double>;
+  constexpr long double ld6  = std::numbers::ln2_v<long double>;
+  constexpr long double ld7  = std::numbers::ln10_v<long double>;
+  constexpr long double ld8  = std::numbers::sqrt2_v<long double>;
+  constexpr long double ld9  = std::numbers::sqrt3_v<long double>;
+  constexpr long double ld10 = std::numbers::inv_sqrt3_v<long double>;
+  constexpr long double ld11 = std::numbers::egamma_v<long double>;
+  constexpr long double ld12 = std::numbers::phi_v<long double>;
+
+  return 0;
+
+}
+
+