How many 4-digit numbers can be formed using the digits 1, 2, 3, 4, 5, 6, 7 if repetition of digits is allowed?

Would that be 840

7 choices for each position, so

7x7x7x7 = 2401

oh ok... thanks

Haw many 4 digit numbers can formed from the digit 1,2,3,4,5,6,and 7 were digit is used at most if the number must be odd

To find the number of 4-digit numbers that can be formed using the digits 1, 2, 3, 4, 5, 6, and 7 with repetition allowed, we can use the rule of product.

For each of the four digits in the number, we have 7 choices (as there are 7 digits to choose from). Since repetition is allowed, each digit can be any of the 7 choices.

Therefore, using the rule of product, we multiply the number of choices for each digit together:

7 choices for the first digit x 7 choices for the second digit x 7 choices for the third digit x 7 choices for the fourth digit = 7 x 7 x 7 x 7 = 2401.

So, there are 2401 different 4-digit numbers that can be formed using the digits 1, 2, 3, 4, 5, 6, and 7 with repetition allowed, not 840.