q1. loop must be executed 5 times
i=3 4 5 6 7 
i<=n
Answer: n = 7
i<=7 will be true for i = 3, 4, 5, 6, 7
and that will execute the loop and print 
hello 5 times

q2. n = 5
i = 10
i > 5 will be True for 
i = 10, 9 , 8, 7, 6
that will execute loop 
5 times and hello will 
be printed 5 times

q3. i = 3
i = 5, 7, 9, 11
n = 11
i<=11
i = 3, 5, 7, 9, 11
will be True and loop will be 
executed 5 times

q4. finds sum of the digits 
of the input number
n = 70
n = 133
n = 3400
n = 1231000

Lets trace the program for 
n = 133
sum=0
n>0 133>0 True
d = 133%10=3
sum=sum+3=3
n=133//10=13
n = 13>0 True
d= 13%10= 3
sum=3+3=6
n=13//10=1
1>0 True
d= 1%10=1
dum=6+1=7
n=1//10=0
0>0 False and loop is terminated

q5. 1 2 3 4 
this program finds the sum of inputs
sum=0
i=0
n = 1
sum = 1
i = 1
n = 2
sum = 1+2=3
i=2
n = 3
sum=3+3=6
i=3
n = 4
sum=6+4=10

2 2 2 4 - correct input as well

1000 -1000 0 10 - correct input as well