diff --git a/src/main/java/fr/insa/gei/angles/Angle.java b/src/main/java/fr/insa/gei/angles/Angle.java
new file mode 100644
index 0000000..e1edb2d
--- /dev/null
+++ b/src/main/java/fr/insa/gei/angles/Angle.java
@@ -0,0 +1,76 @@
+package fr.insa.gei.angles;
+
+public class Angle implements IAngle {
+
+    private double radians;
+
+    protected Angle(double radians) {
+        this.radians = radians;
+    }
+
+    @Override
+    public double toDegrees() {
+        return Math.toDegrees(this.radians);
+    }
+
+    @Override
+    public double toRadians() {
+        return this.radians;
+    }
+
+    @Override
+    public double cos() {
+        return Math.cos(this.radians);
+    }
+
+    @Override
+    public double sin() {
+        return Math.sin(this.radians);
+    }
+
+    @Override
+    public double tan() {
+        return Math.tan(this.radians);
+    }
+
+    @Override
+    public IAngle add(IAngle other) {
+        return new Angle(this.radians + other.toRadians());
+    }
+
+    @Override
+    public IAngle sub(IAngle other) {
+        return new Angle(this.radians - other.toRadians());
+    }
+
+    @Override
+    public IAngle mul(double factor) {
+        return new Angle(this.radians * factor);
+    }
+
+    @Override
+    public IAngle div(double divisor) {
+        return new Angle(this.radians / divisor);
+    }
+
+    @Override
+    public int compareTo(IAngle o) {
+        return Double.compare(this.radians, o.toRadians());
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null || getClass() != obj.getClass())
+            return false;
+        Angle other = (Angle) obj;
+        return Double.compare(this.radians, other.radians) == 0;
+    }
+
+    @Override
+    public String toString() {
+        return String.format("%.2frad", this.radians);
+    }
+
+}
diff --git a/src/main/java/fr/insa/gei/angles/AngleFactory.java b/src/main/java/fr/insa/gei/angles/AngleFactory.java
new file mode 100644
index 0000000..17c7d95
--- /dev/null
+++ b/src/main/java/fr/insa/gei/angles/AngleFactory.java
@@ -0,0 +1,15 @@
+package fr.insa.gei.angles;
+
+public class AngleFactory implements IAngleFactory<Angle> {
+
+    @Override
+    public Angle fromRadians(double radians) {
+        return new Angle(radians);
+    }
+
+    @Override
+    public Angle fromDegrees(double degrees) {
+        return new Angle(Math.toRadians(degrees));
+    }
+
+}
diff --git a/src/main/java/fr/insa/gei/angles/IAngleFactory.java b/src/main/java/fr/insa/gei/angles/IAngleFactory.java
index 2504610..6e4f9c8 100644
--- a/src/main/java/fr/insa/gei/angles/IAngleFactory.java
+++ b/src/main/java/fr/insa/gei/angles/IAngleFactory.java
@@ -1,6 +1,6 @@
 package fr.insa.gei.angles;
 
-public interface IAngleFactory<Angle extends IAngle> {
+public interface IAngleFactory<GAngle extends IAngle> {
 
     /**
      * Construct a new Angle object using the given value in radians.
@@ -8,7 +8,7 @@ public interface IAngleFactory<Angle extends IAngle> {
      * @param radians Value of the angle in radians.
      * @return a new Angle object.
      */
-    public Angle fromRadians(double radians);
+    public GAngle fromRadians(double radians);
 
     /**
      * Construct a new Angle object using the given value in degrees.
@@ -16,7 +16,7 @@ public interface IAngleFactory<Angle extends IAngle> {
      * @param degrees Value of the angle in degrees.
      * @return a new Angle object.
      */
-    public Angle fromDegrees(double degrees);
+    public GAngle fromDegrees(double degrees);
 
     /**
      * Construct a new Angle object corresponding to the arc cosine of the given
@@ -25,7 +25,7 @@ public interface IAngleFactory<Angle extends IAngle> {
      * @param a Value for which to compute the arc cosine.
      * @return a new Angle object.
      */
-    public default Angle acos(double a) {
+    public default GAngle acos(double a) {
         return fromRadians(Math.acos(a));
     }
 
@@ -36,7 +36,7 @@ public interface IAngleFactory<Angle extends IAngle> {
      * @param a Value for which to compute the arc sine.
      * @return a new Angle object.
      */
-    public default Angle asin(double a) {
+    public default GAngle asin(double a) {
         return fromRadians(Math.asin(a));
     }
 
@@ -47,7 +47,7 @@ public interface IAngleFactory<Angle extends IAngle> {
      * @param a Value for which to compute the arc tangent.
      * @return a new Angle object.
      */
-    public default Angle atan(double a) {
+    public default GAngle atan(double a) {
         return fromRadians(Math.atan(a));
     }
 
@@ -59,7 +59,7 @@ public interface IAngleFactory<Angle extends IAngle> {
      * @param x Value for which to compute the arc tangent.
      * @return a new Angle object.
      */
-    public default Angle atan2(double y, double x) {
+    public default GAngle atan2(double y, double x) {
         return fromRadians(Math.atan2(y, x));
     }
 
diff --git a/src/main/java/fr/insa/gei/fractions/Fraction.java b/src/main/java/fr/insa/gei/fractions/Fraction.java
new file mode 100644
index 0000000..d483ad0
--- /dev/null
+++ b/src/main/java/fr/insa/gei/fractions/Fraction.java
@@ -0,0 +1,135 @@
+package fr.insa.gei.fractions;
+
+public class Fraction implements IFraction {
+
+    private final int numerator;
+    private final int denominator;
+
+    protected Fraction(int numerator, int denominator) {
+        if (denominator == 0) {
+            throw new IllegalArgumentException("Denominator cannot be zero.");
+        }
+
+        if (denominator < 0) {
+            numerator = -numerator;
+            denominator = -denominator;
+        }
+
+        final int gcd = this.gcd(Math.abs(numerator), Math.abs(denominator));
+
+        this.numerator = numerator / gcd;
+        this.denominator = denominator / gcd;
+    }
+
+    private int gcd(int a, int b) {
+        while (b != 0) {
+            final int temp = b;
+            b = a % b;
+            a = temp;
+        }
+        return a;
+    }
+
+    @Override
+    public int getNumerator() {
+        return this.numerator;
+    }
+
+    @Override
+    public int getDenominator() {
+        return this.denominator;
+    }
+
+    @Override
+    public IFraction add(IFraction f) {
+        return new Fraction(
+                this.numerator * f.getDenominator() + f.getNumerator() * this.denominator,
+                this.denominator * f.getDenominator());
+    }
+
+    @Override
+    public IFraction add(int value) {
+        return new Fraction(
+                this.numerator + value * this.denominator,
+                this.denominator);
+    }
+
+    @Override
+    public IFraction sub(IFraction f) {
+        return this.add(f.neg());
+    }
+
+    @Override
+    public IFraction sub(int value) {
+        return this.add(-value);
+    }
+
+    @Override
+    public IFraction mul(IFraction f) {
+        return new Fraction(
+                this.numerator * f.getNumerator(),
+                this.denominator * f.getDenominator());
+    }
+
+    @Override
+    public IFraction mul(int value) {
+        return new Fraction(
+                this.numerator * value,
+                this.denominator);
+    }
+
+    @Override
+    public IFraction div(IFraction f) {
+        return new Fraction(
+                this.numerator * f.getDenominator(),
+                this.denominator * f.getNumerator());
+    }
+
+    @Override
+    public IFraction div(int value) {
+        return new Fraction(
+                this.numerator,
+                this.denominator * value);
+    }
+
+    @Override
+    public IFraction inv() {
+        return new Fraction(
+                this.denominator,
+                this.numerator);
+    }
+
+    @Override
+    public IFraction neg() {
+        return new Fraction(
+                -this.numerator,
+                this.denominator);
+    }
+
+    @Override
+    public double toDouble() {
+        return (double) this.numerator / this.denominator;
+    }
+
+    @Override
+    public String toString() {
+        return this.numerator + "/" + this.denominator;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null || getClass() != obj.getClass())
+            return false;
+        Fraction other = (Fraction) obj;
+        return this.numerator * other.denominator == other.numerator * this.denominator;
+    }
+
+    @Override
+    public int compareTo(IFraction other) {
+        // a/b cmp c/d <=> a*d cmp b*c (because both b and d are positive)
+        return Integer.compare(this.numerator * other.getDenominator(), this.denominator * other.getNumerator());
+    }
+
+}
diff --git a/src/main/java/fr/insa/gei/fractions/FractionFactory.java b/src/main/java/fr/insa/gei/fractions/FractionFactory.java
new file mode 100644
index 0000000..5e9a086
--- /dev/null
+++ b/src/main/java/fr/insa/gei/fractions/FractionFactory.java
@@ -0,0 +1,10 @@
+package fr.insa.gei.fractions;
+
+public class FractionFactory implements IFractionFactory<Fraction> {
+
+    @Override
+    public Fraction create(int numerator, int denominator) {
+        return new Fraction(numerator, denominator);
+    }
+
+}
diff --git a/src/main/java/fr/insa/gei/fractions/IFractionFactory.java b/src/main/java/fr/insa/gei/fractions/IFractionFactory.java
index ae68242..5bfb3d9 100644
--- a/src/main/java/fr/insa/gei/fractions/IFractionFactory.java
+++ b/src/main/java/fr/insa/gei/fractions/IFractionFactory.java
@@ -1,6 +1,6 @@
 package fr.insa.gei.fractions;
 
-public interface IFractionFactory<Fraction extends IFraction> {
+public interface IFractionFactory<GFraction extends IFraction> {
 
     /**
      * Creates a fraction with given numerator and denominator.
@@ -9,7 +9,7 @@ public interface IFractionFactory<Fraction extends IFraction> {
      * @param denominator the denominator of the fraction
      * @return a new fraction instance
      */
-    public Fraction create(int numerator, int denominator);
+    public GFraction create(int numerator, int denominator);
 
     /**
      * Creates a fraction with given numerator and denominator equal to 1.
@@ -17,7 +17,7 @@ public interface IFractionFactory<Fraction extends IFraction> {
      * @param numerator the numerator of the fraction
      * @return a new fraction instance
      */
-    public default Fraction create(int numerator) {
+    public default GFraction create(int numerator) {
         return this.create(numerator, 1);
     }