大学入学共通テスト数学 I・A (場合の数と確率（数字カードと整数の桁）) 練習問題

Question

プレポラ AI練習問題

Accepted Answer

To form a 3-digit integer, the hundreds digit cannot be 0.  
- Hundreds digit: 5 choices (1, 2, 3, 4, 5).  
- Tens digit: 5 choices (remaining 5 digits, including 0).  
- Units digit: 4 choices (remaining 4 digits).  
Total = $5 	imes 5 	imes 4 = 100$.