How many 3-digit numbers between 100 and 1000 have a 4 as the mid_英语解答

How many 3-digit numbers between 100 and 1000 have a 4 as the middle digit?的翻译

人气：192 ℃　时间：2020-03-28 08:26:08

解答

在100-1000之间有多少个3位数,并且中间数字是4?