Some directories had a capital in their name [fixed]. Added a recursive factorial algorithm. (#763)

* Renaming directories
* Adding a recursive factorial algorithm

maths/average.py

@@ -0,0 +1,14 @@
+def average(nums):
+    sum = 0
+    n = 0
+    for x in nums:
+      sum += x
+      n += 1
+    avg = sum / n
+    print(avg)
+
+def main():
+  average([2, 4, 6, 8, 20, 50, 70])
+
+if __name__ == '__main__':
+  main()