"Python3 Exercise 019" has a fractional sequence: 2/1,3/2,5/3,8/5,13/8,21/13. Find out the sum of the first 20 items of this series.

After a fraction of the numerator = numerator of the previous fraction + denominator, the denominator of the next fraction = the numerator of the previous fraction, the cycle is 20 times the result. Note that the numerator is a and the denominator is B, although a = a + B,

But at this point A has become a+b, so to re-assign the value of the time, it is (a+b)-B to be equal to the original denominator B, so re-assignment should be written as a-a

Method One

From fractionsImport fraction


def Fibonacci (N):
A, B =1,2
res = [1]
i =1
While i < n:
A, B = b, a+b
Res.append (a)
i + = 1
Else:
return Res

result = Fibonacci (21)

Sum_result = SUM ([Fraction (i[0], i[1]) for I in Zip (result[1:], result[0:-  1]))
Print (Sum_result)                 


Method Two

from fractions import Fraction sum = 0 a, b = 2 , 1 for i in range ( 20 ):      sum = sum + Fraction(a / b)      a = a + b      b = a - b print ( sum )Method Three sum = 0 a, b = 2 , 1 for i in range ( 20 ):      sum = sum + a / b      a = a + b      b = a - b print ( sum )

"Python3 Exercise 019" has a fractional sequence: 2/1,3/2,5/3,8/5,13/8,21/13. Find out the sum of the first 20 items of this series.