QT3.14 is mathematics slang for cutie pie, that is, a cute, attractive person. QT means cutie, and 3.14 means pie (with same pronunciation with Pi). Pi Day is celebrated on March 14th (3/14) around the world.

QT3.14是用数学俚语指代某个可爱又迷人的家伙，这里的QT其实就是cutie（可爱）的缩写，而3.14则代表pie（招人喜欢的人），与该数字原本代表的数学概念Pi（圆周率）同音。世界各地会在每年的3月14日庆祝圆周率日。

For example:

You are such a QT3.14! How can I not like you!

你这么可爱迷人！叫我怎么能不喜欢你呢！