The creator of "+"is15th century German mathematician Wei Demei. He added a vertical bar to the horizontal line to indicate the increase.
The creator of "-"is also a mathematician. He subtracted a vertical bar from the plus sign to indicate the decrease. The symbol "×" is another way to indicate increase, that is, write the plus sign on the diagonal. The creator of ⊙ is/kloc-Hana, Switzerland in the 8th century. It means decomposition, that is, separating two points with a horizontal line. The creator of "=" is16th century English mathematician Luckerd. He thinks that there is nothing more similar in the world than these two parallel and equal line segments, so he uses it to indicate that two numbers are equal. Later, it was widely used by French mathematician Veda and German mathematician Leibniz before it was widely accepted by people.