64.
The difference between the functions discard and remove is that:

65.
What will be the output of the following Python code?
s1={3, 4}
s2={1, 2}
s3=set()
i=0
j=0
for i in s1:
    for j in s2:
        s3.add((i,j))
        i+=1
        j+=1
print(s3)

68.
What is the purpose of the difference() method for sets?