diff --git a/src/fraction.rs b/src/fraction.rs
new file mode 100644
index 0000000..97e0e85
--- /dev/null
+++ b/src/fraction.rs
@@ -0,0 +1,80 @@
+use std::{collections::HashSet, error::Error};
+
+use crate::number::Number;
+
+#[derive(Debug, PartialEq, Eq)]
+pub struct Fraction {
+    numerator: Number,
+    denominator: Number,
+}
+
+pub struct Rational {}
+
+impl Fraction {
+    pub fn new(numerator: Number, denominator: Number) -> Result<Self, Box<dyn Error>> {
+        if denominator == 0.into() {
+            return Err(Box::from("Division by 0"));
+        }
+        let mut f = Fraction {
+            numerator,
+            denominator,
+        };
+        f.reduce();
+        Ok(f)
+    }
+
+    pub fn reduce(&mut self) {
+        let gcd = Number::gcd(self.numerator.clone(), self.denominator.clone());
+        self.numerator = self.numerator.clone() / gcd.clone();
+        self.denominator = self.denominator.clone() / gcd.clone();
+    }
+
+    pub fn get_repeating(&self) -> Number {
+        let mut memory = HashSet::new();
+        let mut div_with = self.numerator.clone();
+        let mut repetition = Vec::new();
+        loop {
+            let (div, rem) = Number::div_with_rem(div_with.clone(), self.denominator.clone());
+            if rem != 0.into() && memory.contains(&rem) {
+                repetition.push(div.digits[0]);
+                return Number {
+                    digits: repetition,
+                    sign: crate::number::Sign::Positif,
+                };
+            }
+            memory.insert(rem.clone());
+            if div.digits.is_empty() {
+                div_with = div_with * 10;
+            } else {
+                repetition.push(div.digits[0]);
+                div_with = rem * 10;
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use crate::number::Number;
+
+    use super::Fraction;
+
+    #[test]
+    fn test_reduce() {
+        let f = Fraction::new(120.into(), 90.into()).unwrap();
+        assert_eq!(
+            f,
+            Fraction {
+                numerator: 4.into(),
+                denominator: 3.into()
+            }
+        );
+    }
+
+    #[test]
+    fn test_repeating() {
+        let f = Fraction::new(1.into(), 7.into()).unwrap();
+        let rep = f.get_repeating();
+        assert_eq!(rep, Number::from("142857"));
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index 40ccb35..7e82089 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,4 +1,5 @@
 pub mod combination;
+pub mod fraction;
 pub mod grid;
 pub mod math;
 pub mod number;
diff --git a/src/math.rs b/src/math.rs
index 11c08c5..0005961 100644
--- a/src/math.rs
+++ b/src/math.rs
@@ -80,3 +80,14 @@ pub fn fib(n: u64) -> u64 {
 
     last_two.0
 }
+
+pub fn gcd(mut a: u64, mut b: u64) -> u64 {
+    loop {
+        let t = b;
+        b = a % b;
+        a = t;
+        if b == 0 {
+            return a;
+        }
+    }
+}
diff --git a/src/number.rs b/src/number.rs
index cf4ecfc..67b3d09 100644
--- a/src/number.rs
+++ b/src/number.rs
@@ -147,7 +147,7 @@ impl Number {
         last_two.0
     }
 
-    fn div_with_rem(n1: Number, n2: Number) -> (Number, Number) {
+    pub fn div_with_rem(n1: Number, n2: Number) -> (Number, Number) {
         let n1_len = n1.digits.len();
         let n2_len = n2.digits.len();
         if n2_len > n1_len {
@@ -196,6 +196,17 @@ impl Number {
         }
         (res, remainder)
     }
+
+    pub fn gcd(mut a: Number, mut b: Number) -> Number {
+        loop {
+            let t = b.clone();
+            b = a % b;
+            a = t;
+            if b == Number::from(0) {
+                return a;
+            }
+        }
+    }
 }
 
 impl From<Number> for isize {
@@ -236,10 +247,11 @@ impl From<&str> for Number {
 }
 
 impl From<isize> for Number {
-    fn from(value: isize) -> Self {
+    fn from(mut value: isize) -> Self {
         let mut sign = Sign::Positif;
         if value < 0 {
             sign = Sign::Negatif;
+            value *= -1;
         }
         let num_len = if value > 0 {
             (value as f64 + 1.0).log10().ceil() as usize
@@ -400,7 +412,7 @@ mod number_tests {
         assert_eq!(
             number,
             Number {
-                digits: vec![1234],
+                digits: vec![1, 2, 3, 4],
                 sign: Sign::Negatif
             }
         );