num = [3,6,9,12]
for i in num(0,4):
    print i * 2

#or or or or or

for i in range(0,len(num)):
    print numbers[i] * 2





#reverse

print number.reverse

# or or or

for i in range(0,len(numbers)):
    print numbers[len(numbers)-i-1]



# merging
