Let's try to do part of it in the head, so I can just write down the answer.

让我们先试试前面的一部分,我就直接写答案了

耶鲁公开课 - 基础物理课程节选

PROFESSOR: -- that this is not a quick clicker question, so you actually need to maybe write something down to figure out the answer.

教授：这个问题不是一眼就能看出来的，你们需要在纸上写一写,才能得到答案。

麻省理工公开课 - 化学原理课程节选