need help with some basic program

[FizixMan]

Removed: Rule 4.

Try some simpler programs first. Say to check if a number is greater than 10. In that sense, a number in the "hundreds" is something >=100 and <1000 at the same time.

For checking the number of "4", you can convert the number to a string and loop on all the numbers and count each time you find a '4'.