81个.十位数字有9种可能性(1、2、⋅⋅、9).本来个位数字有10种可能性(O、1、⋅⋅、9),但要使满足题目条件,个位数字则余下9种可能性.因此,有9*9=81个两位数的十位数字及个位数字互不相同.在所有两位数(10至99)当中,只有11、22、⋅⋅、99不满足题目条件.因此,有90-9=81个两位数的十位数...
百度试题 结果1 题目1. (i) How many one-digit numbers are there? 相关知识点: 试题来源: 解析 There are 9 one-digit numbers. 反馈 收藏
To find out how many 8-digit numbers there are in total, we can follow these steps:Step 1: Identify the smallest and largest 8-digit numbers. - The smallest 8-digit number is 10,000,000 (which is 1 followed by 7 zeros). - The l
To find how many three-digit numbers can be formed with no repeated digits, we can break the problem down into steps based on the placement of the digits.1. Identify the Structure of a Three-Digit Number: A three-digit numbe
Answer to: How many four-digit numbers are there formed from the digits 1, 2, 3, 4, 5 (with possible repetition) that are evenly divisible by 4? By...
How many three-digit numbers are there that have the sum of their digits equal to 10?. 相关知识点: 试题来源: 解析 54.. When the hundred digit is 1:109,118,127,⋯,190,there are 10 numbers; when the hundred digit is 2:208,217,226,⋯,280, there are 9 numbers; when the ...
【题目】17.有多少个三位数,共各位数字的乘积是质数 17. How many three-digit numbers are there such that(注:1不是质数)? the product of their digits is a prime number.(A)15 (B)12 (C)15 (Remember I is nut a prine nuaber.)(D)20 (E)2] (A)15 (B)12 (C)17(D)20 (E)21 ...
How many 3 digit numbers are there, with distinct digits, with each digit odd? View Solution How many three digit numbers are divisible by 7 ? View Solution View Solution View Solution View Solution View Solution Exams IIT JEE NEET UP Board ...
GMAT 考满分题库9*9*8 选b 吧 第一位数9选一 第二位数十选一但是选走了一位数 就是9选一 第三位数 十选一 被选走了两个数 就是8选一 9
How many 3-digit numbers are there, the sum of whose digits is 10? How many 3 digit numbers are there, the sum of whose digits is 9? How many numbers between 1 and 250 are divisible by 6? How many numbers between 1,000 and 9,999 are divisible by 5 or 7?