What is another version of the equals sign that some used in early mathematics?

Answer 1

In early mathematics, one alternative to the equals sign (=) that was used is the "equals" sign represented by two parallel horizontal lines (≡). This symbol was used by some mathematicians to indicate equality in a more rigorous way, often in the context of congruences in number theory. Another less common notation that was historically used is the double dash (⸺), which some early writers employed to signify equivalence.