diff --git a/project_euler/problem_01/sol1.py b/project_euler/problem_01/sol1.py
index 2dbb60cdb16f..385bbbbf43b3 100644
--- a/project_euler/problem_01/sol1.py
+++ b/project_euler/problem_01/sol1.py
@@ -1,7 +1,7 @@
 """
 Problem Statement:
 If we list all the natural numbers below 10 that are multiples of 3 or 5,
-we get 3,5,6 and 9. The sum of these multiples is 23.
+we get 3, 5, 6 and 9. The sum of these multiples is 23.
 Find the sum of all the multiples of 3 or 5 below N.
 """
 
diff --git a/project_euler/problem_01/sol2.py b/project_euler/problem_01/sol2.py
index 212fd40562d1..f08f548cb752 100644
--- a/project_euler/problem_01/sol2.py
+++ b/project_euler/problem_01/sol2.py
@@ -1,7 +1,7 @@
 """
 Problem Statement:
 If we list all the natural numbers below 10 that are multiples of 3 or 5,
-we get 3,5,6 and 9. The sum of these multiples is 23.
+we get 3, 5, 6 and 9. The sum of these multiples is 23.
 Find the sum of all the multiples of 3 or 5 below N.
 """
 
@@ -19,14 +19,14 @@ def solution(n: int = 1000) -> int:
     83700
     """
 
-    sum = 0
+    total = 0
     terms = (n - 1) // 3
-    sum += ((terms) * (6 + (terms - 1) * 3)) // 2  # sum of an A.P.
+    total += ((terms) * (6 + (terms - 1) * 3)) // 2  # total of an A.P.
     terms = (n - 1) // 5
-    sum += ((terms) * (10 + (terms - 1) * 5)) // 2
+    total += ((terms) * (10 + (terms - 1) * 5)) // 2
     terms = (n - 1) // 15
-    sum -= ((terms) * (30 + (terms - 1) * 15)) // 2
-    return sum
+    total -= ((terms) * (30 + (terms - 1) * 15)) // 2
+    return total
 
 
 if __name__ == "__main__":
diff --git a/project_euler/problem_01/sol3.py b/project_euler/problem_01/sol3.py
index faa505615924..67cb83faf238 100644
--- a/project_euler/problem_01/sol3.py
+++ b/project_euler/problem_01/sol3.py
@@ -1,7 +1,7 @@
 """
 Problem Statement:
 If we list all the natural numbers below 10 that are multiples of 3 or 5,
-we get 3,5,6 and 9. The sum of these multiples is 23.
+we get 3, 5, 6 and 9. The sum of these multiples is 23.
 Find the sum of all the multiples of 3 or 5 below N.
 """
 
@@ -22,38 +22,38 @@ def solution(n: int = 1000) -> int:
     83700
     """
 
-    sum = 0
+    total = 0
     num = 0
     while 1:
         num += 3
         if num >= n:
             break
-        sum += num
+        total += num
         num += 2
         if num >= n:
             break
-        sum += num
+        total += num
         num += 1
         if num >= n:
             break
-        sum += num
+        total += num
         num += 3
         if num >= n:
             break
-        sum += num
+        total += num
         num += 1
         if num >= n:
             break
-        sum += num
+        total += num
         num += 2
         if num >= n:
             break
-        sum += num
+        total += num
         num += 3
         if num >= n:
             break
-        sum += num
-    return sum
+        total += num
+    return total
 
 
 if __name__ == "__main__":
diff --git a/project_euler/problem_01/sol4.py b/project_euler/problem_01/sol4.py
index d5e86320da5e..77f323695898 100644
--- a/project_euler/problem_01/sol4.py
+++ b/project_euler/problem_01/sol4.py
@@ -1,7 +1,7 @@
 """
 Problem Statement:
 If we list all the natural numbers below 10 that are multiples of 3 or 5,
-we get 3,5,6 and 9. The sum of these multiples is 23.
+we get 3, 5, 6 and 9. The sum of these multiples is 23.
 Find the sum of all the multiples of 3 or 5 below N.
 """
 
diff --git a/project_euler/problem_01/sol5.py b/project_euler/problem_01/sol5.py
index eae62ef5c75c..256516802ca0 100644
--- a/project_euler/problem_01/sol5.py
+++ b/project_euler/problem_01/sol5.py
@@ -1,15 +1,14 @@
 """
 Problem Statement:
 If we list all the natural numbers below 10 that are multiples of 3 or 5,
-we get 3,5,6 and 9. The sum of these multiples is 23.
+we get 3, 5, 6 and 9. The sum of these multiples is 23.
 Find the sum of all the multiples of 3 or 5 below N.
 """
 
-"""A straightforward pythonic solution using list comprehension"""
-
 
 def solution(n: int = 1000) -> int:
     """Returns the sum of all the multiples of 3 or 5 below n.
+       A straightforward pythonic solution using list comprehension.
 
     >>> solution(3)
     0
diff --git a/project_euler/problem_01/sol6.py b/project_euler/problem_01/sol6.py
index ca08a4a639ab..5f60512a73fb 100644
--- a/project_euler/problem_01/sol6.py
+++ b/project_euler/problem_01/sol6.py
@@ -1,7 +1,7 @@
 """
 Problem Statement:
 If we list all the natural numbers below 10 that are multiples of 3 or 5,
-we get 3,5,6 and 9. The sum of these multiples is 23.
+we get 3, 5, 6 and 9. The sum of these multiples is 23.
 Find the sum of all the multiples of 3 or 5 below N.
 """
 
diff --git a/project_euler/problem_01/sol7.py b/project_euler/problem_01/sol7.py
index 8e53d2a81fb9..5761c00f2996 100644
--- a/project_euler/problem_01/sol7.py
+++ b/project_euler/problem_01/sol7.py
@@ -1,7 +1,7 @@
 """
 Problem Statement:
 If we list all the natural numbers below 10 that are multiples of 3 or 5,
-we get 3,5,6 and 9. The sum of these multiples is 23.
+we get 3, 5, 6 and 9. The sum of these multiples is 23.
 Find the sum of all the multiples of 3 or 5 below N.
 """