1对加法运算律的理解加法交换律就是两个数相加可以用两种不同的方法计算,得数保持不变。等号两边两个算式的相同点是:两个加数没有变,都是加法运算,得数一样;不同点是:左右两边的算式中两个加数的位置交换了位置。因此加法交换律的定义就是:两个数相加,交换两个加数的位置,和不变,这叫做加法交换律。 An understanding of the law of addition Law The law of addition law is the sum of two numbers can be calculated using two different methods, the number remains unchanged. The two points on both sides of the equal sign are the same: the two addends do not change, they are addition operations, the same as the number; the difference is: the positions of two addends in the left and right formulas are swapped. Therefore, the definition of additive exchange law is: two numbers added, the exchange of two addend position, and unchanged, which is called addition exchange law.