diff --git a/src/utility/include/mp_units/math.h b/src/utility/include/mp_units/math.h
index 4f671fd9..e3e9ee2c 100644
--- a/src/utility/include/mp_units/math.h
+++ b/src/utility/include/mp_units/math.h
@@ -127,7 +127,7 @@ template<Quantity Q>
   requires requires { abs(q.number()); } || requires { std::abs(q.number()); }
 {
   using std::abs;
-  return Q(abs(q.number()));
+  return abs(q.number()) * Q::reference;
 }
 
 /**
diff --git a/test/unit_test/runtime/math_test.cpp b/test/unit_test/runtime/math_test.cpp
index 47fc48a4..92fa7168 100644
--- a/test/unit_test/runtime/math_test.cpp
+++ b/test/unit_test/runtime/math_test.cpp
@@ -22,8 +22,8 @@
 
 #include "almost_equals.h"
 #include <catch2/catch_all.hpp>
-#include <mp_units/math.h>
 #include <mp_units/iostream.h>
+#include <mp_units/math.h>
 #include <mp_units/systems/angular/angular.h>
 #include <mp_units/systems/isq/space_and_time.h>
 #include <mp_units/systems/si/unit_symbols.h>
@@ -311,26 +311,26 @@ TEST_CASE("ISQ trigonometric functions", "[trig][isq]")
 {
   SECTION("sin")
   {
-    REQUIRE_THAT(isq::sin(isq::angular_measure[deg](0.)), AlmostEquals(quantity{0.}));
-    REQUIRE_THAT(isq::sin(isq::angular_measure[deg](90.)), AlmostEquals(quantity{1.}));
-    REQUIRE_THAT(isq::sin(isq::angular_measure[deg](180.)), AlmostEquals(quantity{0.}));
-    REQUIRE_THAT(isq::sin(isq::angular_measure[deg](270.)), AlmostEquals(quantity{-1.}));
+    REQUIRE_THAT(isq::sin(0. * isq::angular_measure[deg]), AlmostEquals(0. * one));
+    REQUIRE_THAT(isq::sin(90. * isq::angular_measure[deg]), AlmostEquals(1. * one));
+    REQUIRE_THAT(isq::sin(180. * isq::angular_measure[deg]), AlmostEquals(0. * one));
+    REQUIRE_THAT(isq::sin(270. * isq::angular_measure[deg]), AlmostEquals(-1. * one));
   }
 
   SECTION("cos")
   {
-    REQUIRE_THAT(isq::cos(isq::angular_measure[deg](0.)), AlmostEquals(quantity{1.}));
-    REQUIRE_THAT(isq::cos(isq::angular_measure[deg](90.)), AlmostEquals(quantity{0.}));
-    REQUIRE_THAT(isq::cos(isq::angular_measure[deg](180.)), AlmostEquals(quantity{-1.}));
-    REQUIRE_THAT(isq::cos(isq::angular_measure[deg](270.)), AlmostEquals(quantity{0.}));
+    REQUIRE_THAT(isq::cos(0. * isq::angular_measure[deg]), AlmostEquals(1. * one));
+    REQUIRE_THAT(isq::cos(90. * isq::angular_measure[deg]), AlmostEquals(0. * one));
+    REQUIRE_THAT(isq::cos(180. * isq::angular_measure[deg]), AlmostEquals(-1. * one));
+    REQUIRE_THAT(isq::cos(270. * isq::angular_measure[deg]), AlmostEquals(0. * one));
   }
 
   SECTION("tan")
   {
-    REQUIRE_THAT(isq::tan(isq::angular_measure[deg](0.)), AlmostEquals(quantity{0.}));
-    REQUIRE_THAT(isq::tan(isq::angular_measure[deg](45.)), AlmostEquals(quantity{1.}));
-    REQUIRE_THAT(isq::tan(isq::angular_measure[deg](135.)), AlmostEquals(quantity{-1.}));
-    REQUIRE_THAT(isq::tan(isq::angular_measure[deg](180.)), AlmostEquals(quantity{0.}));
+    REQUIRE_THAT(isq::tan(0. * isq::angular_measure[deg]), AlmostEquals(0. * one));
+    REQUIRE_THAT(isq::tan(45. * isq::angular_measure[deg]), AlmostEquals(1. * one));
+    REQUIRE_THAT(isq::tan(135. * isq::angular_measure[deg]), AlmostEquals(-1. * one));
+    REQUIRE_THAT(isq::tan(180. * isq::angular_measure[deg]), AlmostEquals(0. * one));
   }
 }
 
@@ -338,23 +338,23 @@ TEST_CASE("ISQ inverse trigonometric functions", "[inv trig][isq]")
 {
   SECTION("asin")
   {
-    REQUIRE_THAT(isq::asin(quantity{-1.}), AlmostEquals(isq::angular_measure[deg](-90.)));
-    REQUIRE_THAT(isq::asin(quantity{0.}), AlmostEquals(isq::angular_measure[deg](0.)));
-    REQUIRE_THAT(isq::asin(quantity{1.}), AlmostEquals(isq::angular_measure[deg](90.)));
+    REQUIRE_THAT(isq::asin(-1. * one), AlmostEquals(-90. * isq::angular_measure[deg]));
+    REQUIRE_THAT(isq::asin(0. * one), AlmostEquals(0. * isq::angular_measure[deg]));
+    REQUIRE_THAT(isq::asin(1. * one), AlmostEquals(90. * isq::angular_measure[deg]));
   }
 
   SECTION("acos")
   {
-    REQUIRE_THAT(isq::asin(quantity{-1.}), AlmostEquals(isq::angular_measure[deg](-90.)));
-    REQUIRE_THAT(isq::asin(quantity{0.}), AlmostEquals(isq::angular_measure[deg](0.)));
-    REQUIRE_THAT(isq::asin(quantity{1.}), AlmostEquals(isq::angular_measure[deg](90.)));
+    REQUIRE_THAT(isq::asin(-1. * one), AlmostEquals(-90. * isq::angular_measure[deg]));
+    REQUIRE_THAT(isq::asin(0. * one), AlmostEquals(0. * isq::angular_measure[deg]));
+    REQUIRE_THAT(isq::asin(1. * one), AlmostEquals(90. * isq::angular_measure[deg]));
   }
 
   SECTION("atan")
   {
-    REQUIRE_THAT(isq::atan(quantity{-1.}), AlmostEquals(isq::angular_measure[deg](-45.)));
-    REQUIRE_THAT(isq::atan(quantity{0.}), AlmostEquals(isq::angular_measure[deg](0.)));
-    REQUIRE_THAT(isq::atan(quantity{1.}), AlmostEquals(isq::angular_measure[deg](45.)));
+    REQUIRE_THAT(isq::atan(-1. * one), AlmostEquals(-45. * isq::angular_measure[deg]));
+    REQUIRE_THAT(isq::atan(0. * one), AlmostEquals(0. * isq::angular_measure[deg]));
+    REQUIRE_THAT(isq::atan(1. * one), AlmostEquals(45. * isq::angular_measure[deg]));
   }
 }
 
@@ -367,41 +367,41 @@ TEST_CASE("Angle trigonometric functions", "[trig][angle]")
 
   SECTION("sin")
   {
-    REQUIRE_THAT(sin(angle[deg](0.)), AlmostEquals(quantity{0.}));
-    REQUIRE_THAT(sin(angle[deg](90.)), AlmostEquals(quantity{1.}));
-    REQUIRE_THAT(sin(angle[deg](180.)), AlmostEquals(quantity{0.}));
-    REQUIRE_THAT(sin(angle[deg](270.)), AlmostEquals(quantity{-1.}));
+    REQUIRE_THAT(sin(0. * angle[deg]), AlmostEquals(0. * one));
+    REQUIRE_THAT(sin(90. * angle[deg]), AlmostEquals(1. * one));
+    REQUIRE_THAT(sin(180. * angle[deg]), AlmostEquals(0. * one));
+    REQUIRE_THAT(sin(270. * angle[deg]), AlmostEquals(-1. * one));
 
-    REQUIRE_THAT(sin(angle[grad](0.)), AlmostEquals(quantity{0.}));
-    REQUIRE_THAT(sin(angle[grad](100.)), AlmostEquals(quantity{1.}));
-    REQUIRE_THAT(sin(angle[grad](200.)), AlmostEquals(quantity{0.}));
-    REQUIRE_THAT(sin(angle[grad](300.)), AlmostEquals(quantity{-1.}));
+    REQUIRE_THAT(sin(0. * angle[grad]), AlmostEquals(0. * one));
+    REQUIRE_THAT(sin(100. * angle[grad]), AlmostEquals(1. * one));
+    REQUIRE_THAT(sin(200. * angle[grad]), AlmostEquals(0. * one));
+    REQUIRE_THAT(sin(300. * angle[grad]), AlmostEquals(-1. * one));
   }
 
   SECTION("cos")
   {
-    REQUIRE_THAT(cos(angle[deg](0.)), AlmostEquals(quantity{1.}));
-    REQUIRE_THAT(cos(angle[deg](90.)), AlmostEquals(quantity{0.}));
-    REQUIRE_THAT(cos(angle[deg](180.)), AlmostEquals(quantity{-1.}));
-    REQUIRE_THAT(cos(angle[deg](270.)), AlmostEquals(quantity{0.}));
+    REQUIRE_THAT(cos(0. * angle[deg]), AlmostEquals(1. * one));
+    REQUIRE_THAT(cos(90. * angle[deg]), AlmostEquals(0. * one));
+    REQUIRE_THAT(cos(180. * angle[deg]), AlmostEquals(-1. * one));
+    REQUIRE_THAT(cos(270. * angle[deg]), AlmostEquals(0. * one));
 
-    REQUIRE_THAT(cos(angle[grad](0.)), AlmostEquals(quantity{1.}));
-    REQUIRE_THAT(cos(angle[grad](100.)), AlmostEquals(quantity{0.}));
-    REQUIRE_THAT(cos(angle[grad](200.)), AlmostEquals(quantity{-1.}));
-    REQUIRE_THAT(cos(angle[grad](300.)), AlmostEquals(quantity{0.}));
+    REQUIRE_THAT(cos(0. * angle[grad]), AlmostEquals(1. * one));
+    REQUIRE_THAT(cos(100. * angle[grad]), AlmostEquals(0. * one));
+    REQUIRE_THAT(cos(200. * angle[grad]), AlmostEquals(-1. * one));
+    REQUIRE_THAT(cos(300. * angle[grad]), AlmostEquals(0. * one));
   }
 
   SECTION("tan")
   {
-    REQUIRE_THAT(tan(angle[deg](0.)), AlmostEquals(quantity{0.}));
-    REQUIRE_THAT(tan(angle[deg](45.)), AlmostEquals(quantity{1.}));
-    REQUIRE_THAT(tan(angle[deg](135.)), AlmostEquals(quantity{-1.}));
-    REQUIRE_THAT(tan(angle[deg](180.)), AlmostEquals(quantity{0.}));
+    REQUIRE_THAT(tan(0. * angle[deg]), AlmostEquals(0. * one));
+    REQUIRE_THAT(tan(45. * angle[deg]), AlmostEquals(1. * one));
+    REQUIRE_THAT(tan(135. * angle[deg]), AlmostEquals(-1. * one));
+    REQUIRE_THAT(tan(180. * angle[deg]), AlmostEquals(0. * one));
 
-    REQUIRE_THAT(tan(angle[grad](0.)), AlmostEquals(quantity{0.}));
-    REQUIRE_THAT(tan(angle[grad](50.)), AlmostEquals(quantity{1.}));
-    REQUIRE_THAT(tan(angle[grad](150.)), AlmostEquals(quantity{-1.}));
-    REQUIRE_THAT(tan(angle[grad](200.)), AlmostEquals(quantity{0.}));
+    REQUIRE_THAT(tan(0. * angle[grad]), AlmostEquals(0. * one));
+    REQUIRE_THAT(tan(50. * angle[grad]), AlmostEquals(1. * one));
+    REQUIRE_THAT(tan(150. * angle[grad]), AlmostEquals(-1. * one));
+    REQUIRE_THAT(tan(200. * angle[grad]), AlmostEquals(0. * one));
   }
 }
 
@@ -413,22 +413,22 @@ TEST_CASE("Angle inverse trigonometric functions", "[inv trig][angle]")
 
   SECTION("asin")
   {
-    REQUIRE_THAT(asin(quantity{-1.}), AlmostEquals(angle[deg](-90.)));
-    REQUIRE_THAT(asin(quantity{0.}), AlmostEquals(angle[deg](0.)));
-    REQUIRE_THAT(asin(quantity{1.}), AlmostEquals(angle[deg](90.)));
+    REQUIRE_THAT(asin(-1. * one), AlmostEquals(-90. * angle[deg]));
+    REQUIRE_THAT(asin(0. * one), AlmostEquals(0. * angle[deg]));
+    REQUIRE_THAT(asin(1. * one), AlmostEquals(90. * angle[deg]));
   }
 
   SECTION("acos")
   {
-    REQUIRE_THAT(asin(quantity{-1.}), AlmostEquals(angle[deg](-90.)));
-    REQUIRE_THAT(asin(quantity{0.}), AlmostEquals(angle[deg](0.)));
-    REQUIRE_THAT(asin(quantity{1.}), AlmostEquals(angle[deg](90.)));
+    REQUIRE_THAT(asin(-1. * one), AlmostEquals(-90. * angle[deg]));
+    REQUIRE_THAT(asin(0. * one), AlmostEquals(0. * angle[deg]));
+    REQUIRE_THAT(asin(1. * one), AlmostEquals(90. * angle[deg]));
   }
 
   SECTION("atan")
   {
-    REQUIRE_THAT(atan(quantity{-1.}), AlmostEquals(angle[deg](-45.)));
-    REQUIRE_THAT(atan(quantity{0.}), AlmostEquals(angle[deg](0.)));
-    REQUIRE_THAT(atan(quantity{1.}), AlmostEquals(angle[deg](45.)));
+    REQUIRE_THAT(atan(-1. * one), AlmostEquals(-45. * angle[deg]));
+    REQUIRE_THAT(atan(0. * one), AlmostEquals(0. * angle[deg]));
+    REQUIRE_THAT(atan(1. * one), AlmostEquals(45. * angle[deg]));
   }
 }