diff --git a/src/math/src/mod_arithmetics.cairo b/src/math/src/mod_arithmetics.cairo
index 8f8cd4fa..22ec60d5 100644
--- a/src/math/src/mod_arithmetics.cairo
+++ b/src/math/src/mod_arithmetics.cairo
@@ -7,6 +7,7 @@ use integer::u512;
 /// * `modulo` - modulo.
 /// # Returns
 /// * `u256` - result of modular addition
+#[inline(always)]
 fn add_mod(a: u256, b: u256, modulo: u256) -> u256 {
     let mod_non_zero: NonZero<u256> = integer::u256_try_as_non_zero(modulo).unwrap();
     let low: u256 = a.low.into() + b.low.into();
@@ -25,10 +26,12 @@ fn add_mod(a: u256, b: u256, modulo: u256) -> u256 {
 /// * `modulo` - modulo.
 /// # Returns
 /// * `u256` - modular multiplicative inverse
+#[inline(always)]
 fn mult_inverse(b: u256, modulo: u256) -> u256 {
-    // From Fermat's little theorem, a ^ (p - 1) = 1 when p is prime and a != 0. Since a ^ (p - 1) = a · a ^ (p - 2) we have that 
-    // a ^ (p - 2) is the multiplicative inverse of a modulo p.
-    pow_mod(b, modulo - 2, modulo)
+    match math::u256_guarantee_inv_mod_n(b, modulo.try_into().expect('inverse non zero')) {
+        Result::Ok((inv_a, _, _, _, _, _, _, _, _)) => inv_a.into(),
+        Result::Err(_) => 0
+    }
 }
 
 /// Function that return the modular additive inverse.
@@ -37,6 +40,7 @@ fn mult_inverse(b: u256, modulo: u256) -> u256 {
 /// * `modulo` - modulo.
 /// # Returns
 /// * `u256` - modular additive inverse
+#[inline(always)]
 fn add_inverse_mod(b: u256, modulo: u256) -> u256 {
     modulo - b
 }
@@ -48,6 +52,7 @@ fn add_inverse_mod(b: u256, modulo: u256) -> u256 {
 /// * `modulo` - modulo.
 /// # Returns
 /// * `u256` - result of modular substraction
+#[inline(always)]
 fn sub_mod(mut a: u256, mut b: u256, modulo: u256) -> u256 {
     // reduce values
     a = a % modulo;
@@ -65,6 +70,7 @@ fn sub_mod(mut a: u256, mut b: u256, modulo: u256) -> u256 {
 /// * `modulo` - modulo.
 /// # Returns
 /// * `u256` - result of modular multiplication
+#[inline(always)]
 fn mult_mod(a: u256, b: u256, modulo: u256) -> u256 {
     let mult: u512 = integer::u256_wide_mul(a, b);
     let mod_non_zero: NonZero<u256> = integer::u256_try_as_non_zero(modulo).unwrap();
@@ -79,8 +85,11 @@ fn mult_mod(a: u256, b: u256, modulo: u256) -> u256 {
 /// * `modulo` - modulo.
 /// # Returns
 /// * `u256` - result of modular division
+#[inline(always)]
 fn div_mod(a: u256, b: u256, modulo: u256) -> u256 {
-    mult_mod(a, mult_inverse(b, modulo), modulo)
+    let modulo_nz = modulo.try_into().expect('0 modulo');
+    let inv = math::u256_inv_mod(b, modulo_nz).unwrap().into();
+    math::u256_mul_mod_n(a, inv, modulo_nz)
 }
 
 /// Function that performs modular exponentiation.