Crossword Puzzle One adding things up

Clue: One adding things up

Onetime tribe of the Upper Midwest (SAC with 3 letters)
Things to uphold (IDEALS with 6 letters)
Somewhat upset (e.g. PEEVED with 6 letters)
Updike's "A ___ of Sundays" (MONTH with 5 letters)
Upper arm bones (HUMERI with 6 letters)
Wit Oscar + writer Joyce Carol = things to sow? (WILDEOATES with 10 letters)
Key things? (LIMETREES with 9 letters)
Fine things in Bilbao (ARTES with 5 letters)
Headline about an upcoming lecture by "The March King"? (SOUSATOSPEAK with 12 letters)
Two things to read (e.g. HOROSCOPESMUSIC with 15 letters)