help understand this ex:, and lesson related to this!

Question

programming

Answer 1

a, b = 0, 1
while b < 10:
print(b)
a, b = b, a+b
1
1
2
3
5
8

Answer 2

and also next:
a, b = 0, 1
while b < 1000:
print(b, end=',')
a, b = b, a+b

1,1,2,3,5,8,13,21,34,55,89,144,233,377,610,987,