Such as: I, 2+i, A, X, natural logarithm base E, pi.
Operation symbol
Such as plus sign (+), minus sign (-), multiplication sign (× or), division sign (÷ or/), union of two sets (∩), intersection (∩), root sign (√), logarithm (log, lg, ln) and ratio (:).
Relational character
For example, = is equal sign, ≈ is approximate sign, ≠ is unequal sign, > is greater than sign, > is far greater than sign.
Is this what you want? )