Who knows how to quickly memorise Pi (not using imagination and words)?

'3.1415' '926' '535' '8' '979' '323'

It isn’t necessary to memorize Pi as in questions you usually round to 3.14 or just leave it as Pi. If you really want to memorize it, you can group digits. For example, you can write four digits as a group to help you memorize it. Words and imagination definitely help you to memorize it, but you can memorize it if you don’t want to use these two techniques. Again there is no need to memorize Pi for your study, you can just write Pi or round to 3.14. I hope this answer is helpful for you.