abstract：//2个整数相加的和<meta http-equiv="content-type" content="text/html;charset=utf-8"><?php$ab='1';$bc='2';$dd=$ab+$bc;echo $dd;?>
//2个整数相加的和
<meta http-equiv="content-type" content="text/html;charset=utf-8">
<?php
$ab='1';
$bc='2';
$dd=$ab+$bc;
echo $dd;
?>
Correcting teacher：天蓬老师Correction time：2019-09-11 14:36:07
Teacher's summary：既然是估整数的相加, 就没必要使用数字字符串, 依赖自动类型转换来完成它