<?php
echo "EX1:";
echo "\n";
$a=15;
$b=4;
echo $a+$b;
echo "\n";
echo $a-$b;
echo "\n";
echo $a*$b;
echo "\n";
echo $a/$b;
echo "\n";
echo $a%$b;
echo "\n";
echo "EX2:";
echo "\n";
$score=50;
echo $score;
echo $score;
echo "\n";
$score+=20;
echo $score;
echo "\n";
$score*=2;
echo $score;
echo "\n";
$score-=10;
echo $score;
echo "\n";