In the addition formula, the sum must be greater than two addends, which is wrong. Such as 0+ 1= 1.

When one addend is 0, it is as big as the other addend and generally has more errors with the word "certain". We must think more about special circumstances and find a counterexample.

The number arrangement rule before the plus sign of the addition formula is 1, 2,3, 1, 2,3 ... It is a group. Therefore, the first number of the 40th addition formula must be 1. The number arrangement after the plus sign is 2, 5, 8, 1 1, 14, 17 ... The arrangement rule is An=3n- 1(An stands for the nth number,

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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.

Reference source: Baidu Encyclopedia-Supplement