Adult Children by Stephen Beals for September 30, 2017

The French already tried this.

https://en.wikipedia.org/wiki/French_Republican_Calendar#Ten_days_of_the_week

primidi (first day)

duodi (second day)

tridi (third day)

quartidi (fourth day)

quintidi (fifth day)

sextidi (sixth day)

septidi (seventh day)

octidi (eighth day)

nonidi (ninth day)

décadi (tenth day)