diff --git a/src/decimal.hpp b/src/decimal.hpp
index 16689ea1..f49b1d35 100644
--- a/src/decimal.hpp
+++ b/src/decimal.hpp
@@ -1,6 +1,9 @@
 #ifndef DECIMAL_H
 #define DECIMAL_H
 
+#include <cmath>
+#include <string>
+
 #ifdef LOST_FLOAT_MODE
     typedef float decimal;
     #define STR_TO_DECIMAL(x) std::stof(x)
@@ -18,19 +21,19 @@
 #define DECIMAL(x) (decimal) x
 
 // Math Constants wrapped with Decimal typecast
-#define DECIMAL_M_E             (decimal) 2.7182818284590452354     /* e */
-#define DECIMAL_M_LOG2E         (decimal) 1.4426950408889634074     /* log_2 e */
-#define DECIMAL_M_LOG10E        (decimal) 0.43429448190325182765    /* log_10 e */
-#define DECIMAL_M_LN2           (decimal) 0.69314718055994530942    /* log_e 2 */
-#define DECIMAL_M_LN10          (decimal) 2.30258509299404568402    /* log_e 10 */
-#define DECIMAL_M_PI            (decimal) 3.14159265358979323846    /* pi */
-#define DECIMAL_M_PI_2          (decimal) 1.57079632679489661923    /* pi/2 */
-#define DECIMAL_M_PI_4          (decimal) 0.78539816339744830962    /* pi/4 */
-#define DECIMAL_M_1_PI          (decimal) 0.31830988618379067154    /* 1/pi */
-#define DECIMAL_M_2_PI          (decimal) 0.63661977236758134308    /* 2/pi */
-#define DECIMAL_M_2_SQRTPI      (decimal) 1.12837916709551257390    /* 2/sqrt(pi) */
-#define DECIMAL_M_SQRT2         (decimal) 1.41421356237309504880    /* sqrt(2) */
-#define DECIMAL_M_SQRT1_2       (decimal) 0.70710678118654752440    /* 1/sqrt(2) */
+#define DECIMAL_M_E             (decimal) M_E           /* e */
+#define DECIMAL_M_LOG2E         (decimal) M_LOG2E       /* log_2 e */
+#define DECIMAL_M_LOG10E        (decimal) M_LOG10E      /* log_10 e */
+#define DECIMAL_M_LN2           (decimal) M_LN2         /* log_e 2 */
+#define DECIMAL_M_LN10          (decimal) M_LN10        /* log_e 10 */
+#define DECIMAL_M_PI            (decimal) M_PI          /* pi */
+#define DECIMAL_M_PI_2          (decimal) M_PI_2        /* pi/2 */
+#define DECIMAL_M_PI_4          (decimal) M_PI_4        /* pi/4 */
+#define DECIMAL_M_1_PI          (decimal) M_1_PI        /* 1/pi */
+#define DECIMAL_M_2_PI          (decimal) M_2_PI        /* 2/pi */
+#define DECIMAL_M_2_SQRTPI      (decimal) M_2_SQRTPI    /* 2/sqrt(pi) */
+#define DECIMAL_M_SQRT2         (decimal) M_SQRT2       /* sqrt(2) */
+#define DECIMAL_M_SQRT1_2       (decimal) M_SQRT1_2     /* 1/sqrt(2) */
 
 // Math Functions wrapped with Decimal typecast
 #define DECIMAL_POW(base,power) (decimal) std::pow(base, power)