1:
uses crt;
var a:integer;
begin
clrscr;
write('a='); readln(a);
if a>0 then writeln(a,' la so duong');
if a<0 then writeln(a,' la so am');
if a=0 then writeln(a,' khong la so duong cung khong la so am');
realdn;
end.
2:
uses crt;
var x:longint;
begin
clrscr;
write('nhap x='); readln(x);
if x mod 2=0 then writeln(x,' la so chan');
if x mod 2=1 then writeln(x,' la so le');
readln;
end.
3:
Program GIAI_PHUONG_TRINH_BAC_NHAT; Uses crt; Var a,b,x: real; Begin Clrscr; Writeln('GIAI PHUONG TRINH BAC NHAT: AX + B=0'); Writeln('------------------------------------------------------------'); Write ('Nhap a= '); readln(a); Write ('Nhap b= '); readln(b); If(a=0) then If(b=0) then Writeln(' Phuong trinh co vo so nghiem') Else writeln(' Phuong tring vo nghiem') Else Writeln('Phuong trinh co nghiem x=',-b/a: 4: 2); Readln End.