However, such an approach corresponds to a few dozens bits of entropy at best (some for the approach, some for the length of text used, and a few for the numera

However, such an approach corresponds to a few dozens bits of entropy at best (some for the approach, some for the length of text used, and a few for the numeral depending on whence it comes). As stated by zamalek, the trick to not memorizing many passwords is to use a password manager.