Total number of 2-digit numbers = (99 - 9) = 90 of themEvery number that isn't a perfect square has an even number of factors.2-digit numbers that are perfect squares: 16, 25, 36, 49, 64, and 81 = 6 of themRemaining 2-digit numbers = (99 - 6) = 93 .
36
Using prime factorization, there are 2 three digit numbers with 9 factors: 512 and 768. There are no three digit numbers with 10 or more prime factors. 512=2^9 and 768=3*2^8
Two digit numbers are in the range: 10 to 99. Having both 2 & 5 as factors, means the number will be divisible by 10, so there are nine numbers that fit this:{10, 20, 30, 40, 50, 60, 70, 80, 90}
-2
17
There are 45 such numbers.
72. (with the range of two digit numbers being from 10 to 99).
Well, honey, single digit factors of a number are just the numbers that can divide into that number without leaving a remainder. So, for example, the single digit factors of 12 are 1, 2, 3, 4, and 6. It's like finding out who's invited to the party before you start breaking out the cake.
1
It would help to know which digit. 0 appears in 9 numbers and each of the others in 18 numbers.
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.