Being a home owner
For a lot of adults, coming home from work doesn't necessarily mean free time awaits. Keeping on top of household finances (such as writing cheques, paying bills, setting up accounts etc) is an essential part of keeping the family abode in check. However these could easily be incorporated into maths.
Other tips such as how to remove stains from furniture, ironing, cleaning windows and putting up shelves are also neglected from classrooms despite their practical importance.