Two: break the ten laws. For example, 13-7 can be thought as follows: 10-7+3=6.
Three: continuous subtraction (commonly used method), such as 13-7. You can think of it as' continuous subtraction ': 13-3-4 = 6, which means dividing 7 by 3 and 4.
Four: supplementary method. For example, 13-7 can also think like this: 13- 10+3=6.
In arithmetic, the addition rules involving fractions and negative numbers are designed.
Addition has several important properties. It is interchangeable, which means that the order is not important, it is interrelated, which means that when more than two numbers are added, the order in which the addition is performed is not important. Repeatedly adding 1 is the same as counting; Adding 0 will not change the result. Addition also follows related operations such as subtraction and multiplication.
Addition is one of the simplest digital tasks. The most basic addition: 1+ 1 five-month-old babies and even other animal species can be counted. In primary education, students are taught to calculate the superposition of decimal numbers, starting with one digit, and gradually solving the more difficult number calculation.