diff --git a/FractionTask.pro.user b/FractionTask.pro.user
index aef6d40..c524163 100644
--- a/FractionTask.pro.user
+++ b/FractionTask.pro.user
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE QtCreatorProject>
-<!-- Written by QtCreator 5.0.1, 2021-09-20T15:13:59. -->
+<!-- Written by QtCreator 5.0.1, 2021-09-20T16:34:51. -->
 <qtcreator>
  <data>
   <variable>EnvironmentId</variable>
@@ -74,14 +74,15 @@
     <value type="Qt::CheckState" key="1@C:/Users/Berger.ASGARD/Documents/Git/FractionTask/tst_fractiontest.cpp:test_display">Checked</value>
     <value type="Qt::CheckState" key="1@C:/Users/Berger.ASGARD/Documents/Git/FractionTask/tst_fractiontest.cpp:test_equivalence">Checked</value>
     <value type="Qt::CheckState" key="1@C:/Users/Berger.ASGARD/Documents/Git/FractionTask/tst_fractiontest.cpp:test_inequivalence">Checked</value>
+    <value type="Qt::CheckState" key="1@C:/Users/Berger.ASGARD/Documents/Git/FractionTask/tst_fractiontest.cpp:test_substraction">Checked</value>
    </valuemap>
    <value type="int" key="AutoTest.RunAfterBuild">0</value>
    <value type="bool" key="AutoTest.UseGlobal">true</value>
    <valuelist type="QVariantList" key="ClangCodeModel.CustomCommandLineKey">
     <value type="QString">-fno-delayed-template-parsing</value>
    </valuelist>
-   <value type="bool" key="ClangCodeModel.UseGlobalConfig">true</value>
-   <value type="QString" key="ClangCodeModel.WarningConfigId">Builtin.BuildSystem</value>
+   <value type="bool" key="ClangCodeModel.UseGlobalConfig">false</value>
+   <value type="QString" key="ClangCodeModel.WarningConfigId">{7e16192f-0076-4a4a-bb5d-2bec1fc8c0c7}</value>
    <valuemap type="QVariantMap" key="ClangTools">
     <value type="bool" key="ClangTools.AnalyzeOpenFiles">true</value>
     <value type="bool" key="ClangTools.BuildBeforeAnalysis">true</value>
diff --git a/fraction.cpp b/fraction.cpp
index 4e6cc11..5279bba 100644
--- a/fraction.cpp
+++ b/fraction.cpp
@@ -80,9 +80,9 @@ namespace FractionNS {
   bool Fraction::operator==(const double n) const {
     return (double(m_numerator) / double(m_denominator)) == n;
   }
-  bool Fraction::operator==(const Fraction& n) const {
-    return (this->m_numerator == n.getNumerator())
-        && (this->m_denominator == n.getDenominator());
+  bool Fraction::operator==(const Fraction& other) const {
+    return (this->m_numerator == other.getNumerator())
+        && (this->m_denominator == other.getDenominator());
   }
 
   bool Fraction::operator!=(const int n) const {
@@ -112,8 +112,8 @@ namespace FractionNS {
     return *new Fraction(ownNumeratorPart + otherNumeratorPart, lcm);
   }
 
-  Fraction& Fraction::operator+=(const int other) {
-    this->m_numerator = m_numerator + (other * m_denominator);
+  Fraction& Fraction::operator+=(const int n) {
+    this->m_numerator = m_numerator + (n * m_denominator);
     reduce();
     return *this;
   }
@@ -148,8 +148,8 @@ namespace FractionNS {
   }
 
   Fraction& Fraction::operator-=(const int n) {
-    auto newNumerator = m_numerator - (n * m_denominator);
-    return *new Fraction(newNumerator, m_denominator);
+    m_numerator -= n * m_denominator;
+    return *this;
   };
   Fraction& Fraction::operator-=(const Fraction& other) {
     // Sanity check for Clang
@@ -160,6 +160,27 @@ namespace FractionNS {
     auto ownNumeratorPart = m_numerator * (lcm / m_denominator);
     auto otherNumeratorPart = other.getNumerator() * (lcm / other.getDenominator());
 
-    return *new Fraction(ownNumeratorPart - otherNumeratorPart, lcm);
+    m_numerator = ownNumeratorPart - otherNumeratorPart;
+    m_denominator = lcm;
+    reduce();
+    return *this;
+  }
+
+  Fraction& Fraction::operator*(const int n) const {
+    return *new Fraction(m_numerator * n, m_denominator);
+  }
+  Fraction& Fraction::operator*(const Fraction& other) const {
+    return *new Fraction(m_numerator * other.getNumerator(), m_denominator * other.getDenominator());
+  }
+
+  Fraction& Fraction::operator*=(const int n) {
+    m_numerator *= n;
+    return *this;
+  }
+  Fraction& Fraction::operator*=(const Fraction& other) {
+    m_numerator *= other.getNumerator();
+    m_denominator *= other.getDenominator();
+    reduce();
+    return *this;
   }
 }
diff --git a/fraction.hpp b/fraction.hpp
index 520758a..2dee8c4 100644
--- a/fraction.hpp
+++ b/fraction.hpp
@@ -43,5 +43,11 @@ namespace FractionNS {
 
     Fraction& operator-=(const int);
     Fraction& operator-=(const Fraction&);
+
+    Fraction& operator*(const int) const;
+    Fraction& operator*(const Fraction&) const;
+
+    Fraction& operator*=(const int);
+    Fraction& operator*=(const Fraction&);
   };
 }
diff --git a/tst_fractiontest.cpp b/tst_fractiontest.cpp
index b7f9b5f..ab977a8 100644
--- a/tst_fractiontest.cpp
+++ b/tst_fractiontest.cpp
@@ -1,12 +1,12 @@
 #include <QtTest>
+
 #include <QDebug>
 
 #include "fraction.hpp"
 
 using namespace FractionNS;
 
-class FractionTest : public QObject
-{
+class FractionTest : public QObject {
   Q_OBJECT
 
 public:
@@ -20,17 +20,11 @@ private slots:
   void test_addition();
   void test_inequivalence();
   void test_substraction();
+  void test_multiplication();
 };
 
-FractionTest::FractionTest()
-{
-
-}
-
-FractionTest::~FractionTest()
-{
-
-}
+FractionTest::FractionTest() {};
+FractionTest::~FractionTest() {};
 
 void FractionTest::test_constructor()
 {
@@ -40,7 +34,7 @@ void FractionTest::test_constructor()
   QCOMPARE(f1.getDenominator(), 2);
 
   // Reducible fraction
-  Fraction f2 = Fraction(2,4);
+  Fraction f2 = Fraction(2, 4);
   QCOMPARE(f2.getNumerator(), 1);
   QCOMPARE(f2.getDenominator(), 2);
 
@@ -106,20 +100,21 @@ void FractionTest::test_equivalence()
   QCOMPARE(f4, f7);
   QCOMPARE(f5, f6);
 
-  QCOMPARE(f4, 2.0f/3.0f);
-  QCOMPARE(f4, 2.0/3.0);
+  QCOMPARE(f4, 2.0f / 3.0f);
+  QCOMPARE(f4, 2.0 / 3.0);
 
-  QCOMPARE(f7, 2.0f/3.0f);
-  QCOMPARE(f7, 2.0/3.0);
+  QCOMPARE(f7, 2.0f / 3.0f);
+  QCOMPARE(f7, 2.0 / 3.0);
 
-  QCOMPARE(f5, -2.0f/3.0f);
-  QCOMPARE(f5, -2.0/3.0);
+  QCOMPARE(f5, -2.0f / 3.0f);
+  QCOMPARE(f5, -2.0 / 3.0);
 
-  QCOMPARE(f6, -2.0f/3.0f);
-  QCOMPARE(f6, -2.0/3.0);
+  QCOMPARE(f6, -2.0f / 3.0f);
+  QCOMPARE(f6, -2.0 / 3.0);
 }
 
-void FractionTest::test_inequivalence() {
+void FractionTest::test_inequivalence()
+{
   Fraction f1 = Fraction(1, 1);
   Fraction f2 = Fraction(-1, 1);
   Fraction f3 = Fraction(2, 3);
@@ -146,15 +141,16 @@ void FractionTest::test_addition()
   QCOMPARE(f2, 0.5f);
 
   Fraction f3 = Fraction(-2, 9);
-  QCOMPARE(f3, -(2.0/9.0));
-  QCOMPARE(f3, -(2.0f/9.0f));
+  QCOMPARE(f3, -(2.0 / 9.0));
+  QCOMPARE(f3, -(2.0f / 9.0f));
   f3 += Fraction(2, 9);
   QCOMPARE(f3, 0);
   QCOMPARE(f3, 0.0);
   QCOMPARE(f3, 0.0f);
 }
 
-void FractionTest::test_substraction() {
+void FractionTest::test_substraction()
+{
   Fraction f1 = Fraction(11) - 10;
   QCOMPARE(f1, 1);
 
@@ -169,6 +165,35 @@ void FractionTest::test_substraction() {
   Fraction f4 = Fraction(9, 3);
   f4 -= 3;
   QCOMPARE(f4, 0);
+
+  Fraction f5 = Fraction(8, 3);
+  // (8/3) - ((2/3) - 1)
+  //=(8/3) + (1/3)
+  //= 9/3
+  //= 3
+  f5 -= Fraction(2, 3) - 1;
+  QCOMPARE(f5, 3);
+
+  Fraction f6 = Fraction(-2, 199);
+  // (-2/199) + 8
+  //=(-2/199) + (1592/199
+  //=(1590/199)
+  f6 -= Fraction(-4) - 4;
+  QCOMPARE(f6, Fraction(1590, 199));
+}
+
+void FractionTest::test_multiplication()
+{
+  Fraction f1 = Fraction(1, 1);
+  const Fraction f2 = Fraction(2, 1);
+  QCOMPARE(f1 * 2, f2);
+  f1 *= 2;
+  QCOMPARE(f1, f2);
+
+  f1 *= 3;
+  QCOMPARE(f1, 6);
+
+  QCOMPARE(f1 * Fraction(2, 3), 4);
 }
 
 QTEST_APPLESS_MAIN(FractionTest)