echo $zhang+$lisi; # Output 355
echo $zhang-$lisi; # Output 5
echo 20 % 7; # Output 6
if(3>2) echo ‘True‘;
else echo ‘False‘;
# Output True
$score = 60; if($score>=60) echo ‘及格‘;
else echo ‘不及格‘;
# Output 及格
原文：https://www.cnblogs.com/burp/p/14400957.html