15:
uses crt;
var i: integer;
t: real;
begin
clrcsr;
while i<=100 do
begin
i:=i+1;
t:=t+1/i;
end;
write ('tong la: ',t:1:2);
readln;
end.
16:
uses crt;
var n,i: integer;
k: boolean;
begin
clrscr;
k:=true;
write ('nhap n: '); readln (n);
if (n=0) or (n=1) then k:=false
else if n=2 then k:=true
else
for i:=2 to n-1 do if n mod i=0 then k:=false;
if k=true then writeln (n,' la so nguyen to')
else writeln (n,' khong phai la so nguyen to');
readln;
end.
#Anonymous
