To find the number of three-digit positive integers with digits whose product is 24, we can break down 24 into its prime factors: 2 x 2 x 2 x 3. The possible combinations for the three digits are (2, 2, 6), (2, 3, 4), and (2, 4, 3). These can be arranged in 3! ways each, giving a total of 3 x 3! = 18 three-digit positive integers.
Three of them.
50%
There are 20.
A bijective numeration is a numeral system which uses digits to establish a bijection between finite strings and the positive integers.
20. 16 without repeating a digit.
Three of them.
81
The sum of all the digits of all the positive integers that are less than 100 is 4,950.
279,999,720
50%
They are 13.
52
There are none.
Every number from 100 to 999 inclusive !
3
The sum of the digits is 6.
The 2-digit number must be 20, because it is the only 2-digit number whose sum of its two even digits, 2 + 0 = 2, is greater than the product of its two even digits, 2 x 0 = 0. Moreover, 20 is a product of the two consecutive integers 4 and 5.