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已知两个数的和以及这两个数的差,要求这两个数各是多少的数学问题,叫和差问题。和差问题的数量关系式是:(和-差)小数;(和+差)÷2=大数。关系式的由来,可通过画图得到(如下图),根据图可以看出:大数与小数的和减去它们的差是小数的2倍,则(和一差)÷2=小数;大数与小数的和加上它们的差是大数的2倍,则(和+差)÷2=大数。
It is known that the sum of two numbers and the difference between the two numbers require mathematical problems, called the sum and difference problems, which are each of these two numbers. The quantitative relationship between the problem and the difference is: (and - difference) decimal; (and + difference) ÷ 2 = large number. The relationship between the origin, can be obtained by drawing (see below), according to the figure can be seen: the difference between the big and the decimal and their difference is 2 times the decimal, then (and a difference) ÷ 2 = decimal; And the sum of the decimals and their difference is 2 times the large number, then (and + difference) ÷ 2 = large number.