diff --git a/polynomial.py b/polynomial.py
index 6ea1a7d6ca6c9cd90ca38f6baccaad5549c7175a..1f0ae3a956c099795c8b382be82efb64cebda0a8 100644
--- a/polynomial.py
+++ b/polynomial.py
@@ -147,11 +147,12 @@ def compute_lagrange_polynomial(points, prime_number):
                 poly_li *= dividend
                 divider *= (points[i][0] - points[k][0])
 
-        divider = 1 / divider
+        divider = modular_inverse(divider, prime_number)
         point_yi = points[i][1]
         poly_li = poly_li * Polynomial((divider,)) * Polynomial((point_yi,))
 
         lagrange += poly_li
+        lagrange %= prime_number
 
     return lagrange