Could you explain me how to calculated pls ( for loop )

Question

a=1;b=1
for i in range(9):
a,b=b,a+b
print(b/a)

results
2.0
1.5
1.6666666666666667
1.6
1.625
1.6153846153846154
1.619047619047619
1.6176470588235294
1.6181818181818182

I would like to know how to calculated

Answer 1

when the loop runs first a=1 and b=2
2/1=2.0
When loop runs second time
a=2 and b=3
3/2=1.5
Third time a=3 and b=2+3=5
5/3 =1.6666
And so on

Answer 2

May be you can tell us what you want to achieve? Please make samples and give us input values, and how your output should be. Thanks!

Answer 3

okay thank you for the answers !
at first when I saw the question
I thought that should be like (a),(b=b),(a+b)
so that made me confuse, it should be like this (a,b)=(b,a+b)