Uses Math;

var
  ff:Extended;
begin
  ff:=5.16;
  ShowMessage(IntToStr(Trunc(aa)));           //截取整数，小数不要
  ShowMessage(IntToStr(Floor(aa)));            //往小取整
  ShowMessage(IntToStr(Ceil(aa)));              //往大取整
  ShowMessage(IntToStr(Round(aa)));         //四舍五入取整
end;