diff --git a/Python/p010.py b/Python/p010.py
index 9b51251..61ef817 100644
--- a/Python/p010.py
+++ b/Python/p010.py
@@ -6,10 +6,12 @@ from projecteuler import sieve
 def main():
     start = default_timer()
 
-    primes = sieve(2000000)
+    N = 2000000
+
+    primes = sieve(N)
     sum_ = 0
 
-    for i in range(2000000):
+    for i in range(N):
         if primes[i] == 1:
             sum_ = sum_ + i
 
diff --git a/Python/p028.py b/Python/p028.py
index 69f8919..8ad1c49 100644
--- a/Python/p028.py
+++ b/Python/p028.py
@@ -5,7 +5,9 @@ from timeit import default_timer
 def main():
     start = default_timer()
 
-    limit = 1001 * 1001
+    N = 1001
+
+    limit = N * N
 
     i = 0
     j = 1
diff --git a/Python/p035.py b/Python/p035.py
index d52362e..c5fbc06 100644
--- a/Python/p035.py
+++ b/Python/p035.py
@@ -31,10 +31,12 @@ def main():
 
     global primes
 
-    primes = sieve(1000000)
+    N = 1000000
+
+    primes = sieve(N)
     count = 13
 
-    for i in range(101, 1000000, 2):
+    for i in range(101, N, 2):
         if is_circular_prime(i):
             count = count + 1
 
diff --git a/Python/projecteuler.py b/Python/projecteuler.py
index cb58e7b..a433aaa 100644
--- a/Python/projecteuler.py
+++ b/Python/projecteuler.py
@@ -45,14 +45,14 @@ def sieve(n):
     primes[2] = 1
     primes[3] = 1
 
-    for i in range(4, n, 2):
+    for i in range(4, n -1, 2):
         primes[i] = 0
         primes[i+1] = 1
 
     limit = floor(sqrt(n))
 
     for i in range(3, limit, 2):
-        if primes[i]:
+        if primes[i] == 1:
             for j in range(i * i, n, 2 * i):
                 primes[j] = 0