标题: 求问一道数学代数题:324,700和458600之间十位数是一且个位数是3的整数？ [打印本页] 作者: serenaxiaoxiao 时间: 2012-1-30 02:10 标题: 求问一道数学代数题:324,700和458600之间十位数是一且个位数是3的整数？ how many integers between 324,700 and 458,600 have tens digit 1 and units digit 3? (a) 10.300 (b) 10.030 (c) 1.353 (d) 1.352 (e) 1.339 本题答案为E。 新东方黄皮书上的解答是4586-3247=1339，看不懂呀！求高人指点，感激不尽！呜呜！作者: sdcar2010 时间: 2012-1-30 04:41
The first or smallest one is 324713. The last or biggest one is 458513.
Then it is like counting from 1 to 100: (100-1)+1 = 100
In this case counting from 324713 to 458513: (4585-3247) + 1 = 4586-3247