$score=90;
if($score > 80){
echo 'grade 4';
}else if($score > 75){
echo 'grade 3.5';
}else if($score > 70){
echo 'grade 3';
}else if($score > 65){
echo 'grade 2.5';
}else if($score > 60){
echo 'grade 2';
}else if($score > 55){
echo 'grade 1.5';
}else if($score > 50){
echo 'grade 1';
}else{echo'grade0';}
?>
