<?php
$score=98;
if($score<50){
echo'grade 0';
}else if($score<56){
echo 'grade1';
}else if($score<60){
echo 'grade1.5';
}else if($score<65){
echo 'grade2';
}else if($score<70){
echo 'grade2.5';
}else if($score<75){
echo 'grade3';
}else if($score<80){
echo 'grade3.5';
}else{echo 'grade4';}
?>
