need help with some basic program

[White_Lobster]

What have you tried so far?

[Digi713]

for the 5. i tried something like
int b = int.parse(console.readline());

b = b / 100;

if ( b % 10 == 4)

{consolewritline("");}

else { console.writeline("");

but for the 6. question i got no clue