4
Simple enough to solve. The answer is a power of two. Assuming you have two possible digits, say for example, 3 and 4, then you simply have to multiply it by how many numbers you want to get the total number of combinations. Each number can be 3 or 4 in this case, and you have 5 numbers. That's two to the fifth. Five combinations of any two numbers. 2x2x2x2x2. The answer is 32 combinations.
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.
There is 1 combination of all ten numbers, 10 combinations of one number and of nine numbers, 45 combinations of two or eight numbers, 120 combinations of three or seven numbers, 210 combinations of four or six numbers and 252 combinations of five numbers. That is 1023 = 210 - 1 in total.
95
To determine how many numbers have a sum of digits equal to nine, we consider the possible combinations of digits that add up to nine. These combinations include (9,0), (8,1), (7,2), (6,3), and (5,4). Therefore, there are five possible combinations of digits that sum up to nine.
45
The 120 combinations for the digits 1, 2, 3, 4, and 5 refer to the permutations of these five distinct digits. Each arrangement of these digits counts as a unique combination, and since there are 5 digits, the total number of permutations is calculated as 5! (5 factorial), which equals 120. Examples include 12345, 12354, 12435, and so on, continuing through all possible arrangements of these five numbers.
24680 using only even numbers or 12346 which is an even number
252 combinations, :)
Five-digit combinations of numbers from 0 to 9 can range from 00000 to 99999. Each digit can independently be any number from 0 to 9, leading to a total of 10 options per digit. Consequently, there are (10^5) or 100,000 possible combinations. Each combination can include repeated digits and leading zeros.
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.
98,764