No number satisfies all of those conditions.
12
No factor of 9 has three digits. 450 is a three-digit multiple of 150 (and of 9) with a digit sum of 9.
If they are multiples of 9, the digits add up to a multiple of 9.
12
450 or 900
If the sum of the digits of a given number equals nine or a multiple of nine, nine is a factor of that number.
If that is the case, then three is a factor of the original number.
12
12
No factor of 9 has three digits. 450 is a three-digit multiple of 150 (and of 9) with a digit sum of 9.
Yes 18 times 2 equals 36 It is a factor, not a [proper] multiple.
If they are multiples of 9, the digits add up to a multiple of 9.
450 or 900
12
It shows the relationship of factors to multiples. A factor times a factor equals a multiple of both of those factors.
15 or 35
If the last two digits of your target number are a multiple of 4, 4 is a factor of the whole number.