<p><img src="https://img.julecn.com/tk/dgh/ibfvrkqmwvxunrie.png" alt="四舍五入8.5"></p>
<p><img src="https://img.julecn.com/tk/sxh/qzegtvcctcrmruux.png" alt="向下取整8.5"></p>
<p><img src="https://img.julecn.com/tk/tog/rcgwstxzcdehymwq.png" alt="asdfghjk的字符数"></p>
<p><img src="https://img.julecn.com/tk/ixo/npkmtlxpnlgzecov.png" alt="56789的第4个字符"></p>
