All nonzero numbers have an infinite amount of multiples.
1 and 1
1 and 2
4 numbers less than 70 that are multiples of 3 and 5
109 whole numbers greater than 9 and less than 999 are multiples of 9
Prime and odd numbers
3. All other multiples of 3 are not prime.
There are 3 such numbers: 30, 60, 90.
Their sum is 1200.
The multiples of 5 that are also multiples of 6 are multiples of their LCM. The LCM of 5 and 6 is 30, so the question becomes which multiples of 30 are less than 100? The solution is the numbers: 30, 60, 90
The following numbers are multiples of 4: 52 56 60 64 68
50
The LCM of two consecutive numbers is their product. The LCM of two consecutive multiples of 5 is their product divided by 5. Two consecutive numbers cannot be multiples of 5.