Summation and Double Summation examples for the Loops post @ http://nitstorm.github.io/blog/

double_summation.py

x = int(input("Enter x upper limit:"))
y = int(input("Enter y upper limit:"))
total = 0
i,j = 1,1
while i <= y:
	while j <= x:
		total = total + (x*y)
		j += 1
	i += 1
print total

summation.py

total = 0
for n in range(1,100):
	total = total + (2*n)
print total