Every one of the 5 digits can be either a 5 or a 9 so that means 2 choices for the first, 2 for the second digit, etc. There are 2^5 permutations of the numbers 5 and 9 in a 5 digits number.
7
99,997
A five digit number is a number consisting of five digits. eg. 12345 54321 98765
All five digit numbers have three digits. The smallest five digit whole number is 10,000
11112
To find the number of 5-digit combinations from 1 to 20, we first calculate the total number of options for each digit position. Since the range is from 1 to 20, there are 20 options for the first digit, 20 options for the second digit, and so on. Therefore, the total number of 5-digit combinations is calculated by multiplying these options together: 20 x 20 x 20 x 20 x 20 = 3,200,000 combinations.
The answer will depend on how many digits there are in each of the 30 numbers. If the 30 numbers are all 6-digit numbers then the answer is NONE! If the 30 numbers are the first 30 counting numbers then there are 126 combinations of five 1-digit numbers, 1764 combinations of three 1-digit numbers and one 2-digit number, and 1710 combinations of one 1-digit number and two 2-digit numbers. That makes a total of 3600 5-digit combinations.
There are two choices (number 2 or number 3) for each of the five digits. The number of combinations is therefore, 2 x 2 x 2 x 2 x 2 = 32
99997
7
11112
99,997
A five digit number is a number consisting of five digits. eg. 12345 54321 98765
All five digit numbers have three digits. The smallest five digit whole number is 10,000
If zero is permitted as the first digit then the number of combinations is 10 x 10 x 10 x 10 x 10 = 100000 If zero is not permitted then the number of combination is :- 9 x 10 x 10 x 10 x 10 = 90000
11112
the largest five digit number that can be formed using the digits 7 and 9 is 97,000