s1 = input("enter a number")
s2 = input("enter second number")
s3 = input("enter third number")
list1 = [s1,s2,s3]
for i in list1:
  if(len(i)==1):
    i = int(i) + 7
    print (i)
  elif(len(i)==2):
    i = int(i)**5
    print(i)
  elif(len(i)==3):
    s4 = input("enter another number")
    j = int(s3) + int(s4)
    print(j)


here i didn't understand the concept of printing it's unit values. :(