diff --git a/maths/prime.c b/maths/prime.c
index 507cf95..4128933 100644
--- a/maths/prime.c
+++ b/maths/prime.c
@@ -19,7 +19,7 @@ bool isPrime(int number) {
         return false;
     }
 
-    for (int i = 3, limit = /*(int) sqrt(number)*/number; i <= limit; i += 2) {
+    for (int i = 3, limit = (int) sqrt(number); i <= limit; i += 2) {
         if (number % i == 0) {
             return false;
         }