Crossword puzzle clue "math items represented using and"

Math items represented using { and }

Math item represented using a plus or a sigma

Math, of English, Math, History and Biology?

"Math puns are the first ____ of madness" (math pun)

Angle irons graphically represented by four sets of black squares in this grid, and by letter formations starting in the four longest answers

Psalm 100 excerpt suggested by six puzzle answers and graphically represented by certain black squares in this puzzle

Principle represented by the yin and yang

It's represented by a red, white, and blue flag