Name a math symbol

The rarest possible answer — almost no player finds it.

• Aleph— Cantor's symbol for measuring different sizes of infinity itself.
• Nabla— Named for an ancient harp whose triangular shape it resembles.

Genuinely obscure. Most players never think of it.

• Angle symbol
• Arrow
• Because symbol— Upside-down therefore, meaning 'since' at the top of proofs.
• Chi
• Congruent sign
• Element of symbol
• Empty set symbol
• Epsilon
• Euler's number
• Floor brackets
• For all symbol
• Gamma
• Integral sign— Leibniz's elongated 'S' stands for the Latin word summa.
• Intersection symbol
• Lambda
• Long division symbol— Its official Unicode name is simply 'long division.'
• Modulo
• Mu
• Not sign
• Omega
• Parallel symbol
• Partial derivative symbol
• Per mille sign— Percent's stricter sibling, meaning parts per thousand instead of per hundred.
• Perpendicular symbol
• Prime symbol
• Product notation— Sigma's multiplying cousin, taking the product of a sequence instead.
• Proportional to symbol
• QED symbol— A small square used instead of writing out 'quod erat demonstrandum.'
• Rho
• Subset symbol
• Summation sign— Capital sigma tells you to add up every term in a sequence.
• Tau
• There exists symbol
• Therefore symbol— Three dots in a triangle, meaning 'as a result' in proofs.
• Triple bar
• Union symbol
• Zeta

Uncommon — only a minority of players land here.

• Absolute value bars
• Alpha
• Approximately equal sign
• Beta
• Braces
• Brackets
• Caret
• Colon— Reads as 'to' in a ratio such as 3:4.
• Degree sign
• Delta
• Ellipsis— Stands in for the terms you skipped writing out.
• Factorial— 5! means 5×4×3×2×1, which equals 120.
• Fraction bar
• Not equal sign
• Parentheses
• Plus-minus sign
• Theta

A solid, middling pick shared with plenty of other players.

• Asterisk— Doubles as the multiplication sign on any keyboard or spreadsheet.
• Decimal point
• Greater than sign
• Infinity symbol
• Less than sign
• Percent sign
• Pi
• Slash— Shorthand for division in fractions and ratios, like 3/4.
• Square root sign

An overthought pick that scores below the middle of the board.

• Golden ratio— Divides a line so the parts mirror the whole's proportion.
• Imaginary unit— Squaring it gives negative one, which no real number manages.

The most common answer on the board.

• Division sign
• Equals sign
• Minus sign
• Multiplication sign
• Plus sign