Xiaoyue wrote a four-digit number, Dongdong erased the ones digit of the four-digit number, and turned it into a three-digit number, and Archie erased the ones digit of the three-digit number, and turned it into a two-digit number Finally, add these three numbers together, and the result is exactly 7826. What was the four-digit number that Xiaoyue originally wrote?
小悦写了一个四位数，冬冬把这个四位数的个位抹掉，变成了一个三位数，阿奇又把这个三位数的个位抹掉，变成了一个两位数，最后把这三个数加起来，结果刚好是7826．小悦原来写的四位数是多少？
<result>7_051</result>