The equations of the world, addition, subtraction, multiplication and division are all the same calculations.
2. Reading history makes people wise, reading poetry makes people thorough, mathematics makes people careful, physics makes people deep, ethics makes people grave, logic and rhetoric make people able to contend-Bacon.
3. The trajectory of life is in the curvature of the curve; Time scales include addition, subtraction, multiplication and division.
4. Draw a line, and the discerning person will judge whether it is straight or not; Talking about geometry, proudly showing Fiona Fang the way.