How many different four-digit numbers can you form using the digits 1, 2, 3, 5, 6, 7, and 9 with repetition allowed?

Would the answer be,

7*7*7*7?

Thanks

yes, it would.

Use your combination and permutations

Yes, you are correct. To calculate the number of different four-digit numbers that can be formed using the digits 1, 2, 3, 5, 6, 7, and 9 with repetition allowed, you need to consider the number of choices you have for each of the four positions.

Since repetition is allowed, for each position, you have 7 choices (the digits 1, 2, 3, 5, 6, 7, or 9 can be selected).

So, to find the total number of different four-digit numbers, you multiply the number of choices for each position:

7 * 7 * 7 * 7 = 2401

Therefore, there are 2401 different four-digit numbers that can be formed using the given digits with repetition allowed.