Question by Summer Clouds - Discuss with MathYouLike

Summer Clouds moderators

14/11/2017 at 08:51

How many different, positive four-digit integers, with no repeated digits, can be formed using the digits 0 through 9?

List of answers

Cậu Bé Ngu Ngơ 15/11/2017 at 13:02

There are 9 choices to choose the first digit

There are : 10 - 1 = 9 choices to choose the second digit

There are : 10 - 2 = 8 choices to choose the third digit

There are : 10 - 3 = 7 choices to choose the last digit

The answer is : 9 x 9 x 8 x 7 = 4536 (numbers)
Phan Thanh Tinh Coordinator 14/11/2017 at 10:01

There are 9 choices to choose the first digit

There are : 10 - 1 = 9 choices to choose the second digit

There are : 10 - 2 = 8 choices to choose the third digit

There are : 10 - 3 = 7 choices to choose the last digit

The answer is : 9 x 9 x 8 x 7 = 4536 (numbers)

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