60 numbers
30, 60 and 90.
45 multiples of 2 plus 30 multiples of 3 minus 15 multiples of 6 equals 60 numbers
lcm(2, 3, 5) = 30 → 2 digit common multiples are 30, 60, 90.
Multiple of both 2 and 3 <=> multiple of 6 So require 2 digit multiples of 6. 2*6 = 12 and 16*6=96 So the answer is 16-2+1 = 15
-3
There are 13 two-digit multiples of 7.
12, 24, 36, 48, 60, 72, 84, and 96 are.
The 3-digit counting numbers are 100 through 999 = 900 numbers.Half them are multiples of 2 (even numbers).The other half are not . . . 450 of them.
3
6 and 12 are multiples of 2 & 3
The prime factors of 81 are 3, 3, 3, and 3 - so the only two-digit factor is 27, which is 3 x 3 x 3.