AMC 8 2025 Problem 23
AMC8 2025 年第 23 题
整除与因数★★★★☆
How many four-digit numbers have all three of the following properties? (I) The tens and ones digit are both 9. (II) The number is 1 less than a perfect square. (III) The number is the product of exactly two prime numbers.
请问有多少个四位数同时满足以下三个条件？ （一）十位上的数字和个位上的数字都是9。 （二）该数比一个完全平方数小1。 （三）该数正好是两个质数的乘积。
- A.0
- B.1
- C.2
- D.3
- E.4
正确答案 · Correct Answer
B
解析 · Solution
解析整理中
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