1.
var n: integer;
begin
repeat
write('Nhap so n: '); readln(n);
until (n>=10) and (99>=n);
writeln('Chu so hang chuc la: ', n div 10);
writeln('Chu so hang don vi la: ', n mod 10);
end.
2.
var n,i: integer;
s: string;
begin
repeat
write('Nhap so n: '); readln(n);
until (n>=100) and (999>=n);
write('So moi la: ');
str(n,s);
for i:=length(s) downto 1 do write(s[i]);
end.