The first stage is to use physical addition and subtraction, and the calculation is to use concrete things and charts as tools.

The second stage is to imagine abstract numbers into concrete and vivid things with representations, such as common oral application questions, and the concrete thinking in images transits to the embryonic stage of abstract logical thinking.

The third stage is to use abstract numbers and symbols to calculate, which requires children to master the concept of numbers and operate through logical thinking.

Digital introduction:

There are several kinds of numbers, and Arabic numerals are the most common one. Arabic numerals were not invented by Arabs, but by Indians. In fact, it should be listed as Hindi, but it spread to Arabia first and then to the world, so it is called "Arabic numerals".

Numbers are written symbols used to represent numbers. Different counting systems can use the same number.