Well honey, there are only two 2-digit prime numbers that have 4 as one of their digits: 41 and 43. So if you're looking for more, tough luck, there ain't any. You can thank me later for keeping it short and sweet.
There are 5460 five digit numbers with a digit sum of 22.
There is no simple formula for that; I suggest you look up the prime numbers in a table of prime numbers, analyzing each prime number in the range 10-99 whether it fulfills this specific criterion.
To find the even two-digit numbers where the sum of the digits is 5, we need to consider the possible combinations of digits. The digits that sum up to 5 are (1,4) and (2,3). For the numbers to be even, the units digit must be 4, so the possible numbers are 14 and 34. Therefore, there are 2 even two-digit numbers where the sum of the digits is 5.
There are 60480 numbers.
There are 5760 such numbers.
there are 4
61 42 56 89
There are 21 two-digit prime numbers.
With 123 digits you can make 123 one-digit numbers.
There are 5460 five digit numbers with a digit sum of 22.
The numbers from 1 to 39 include both single-digit and double-digit numbers. There are 9 single-digit numbers (1 to 9) and 30 double-digit numbers (10 to 39). Therefore, the total number of digits is 9 (from single-digit numbers) + 60 (from double-digit numbers, as each has 2 digits) = 69 digits in total.
3 41 43 47
27 three digit numbers from the digits 3, 5, 7 including repetitions.
There is no simple formula for that; I suggest you look up the prime numbers in a table of prime numbers, analyzing each prime number in the range 10-99 whether it fulfills this specific criterion.
5040 different 4 digit numbers can be formed with the digits 123456789. This is assuming that no digits are repeated with each combination.
There are 9 digits that can be the first digit (1-9); for each of these there is 1 digit that can be the second digit (6); for each of these there are 10 digits that can be the third digit (0-9); for each of these there are 10 digits that can be the fourth digit (0-9). → number of numbers is 9 × 1 × 10 × 10 = 900 such numbers.
7 two-digit numbers.