3, 6, 9
531 is one of them and that any 3 digit number whose digital sum is 9 is also divisible by 9
All 4 digit numbers that are divisible by 9 are also divisible by 3. The first is 1008 and the last is 9999.
144 is divisible by 12 and 9.
999
3, 6, 9
100. The highest 3 digit number divisible by 9 is 999 (111 times). The highest 2 digit number divisible by 9 is 99 (11 times). The difference is 100.
531 is one of them and that any 3 digit number whose digital sum is 9 is also divisible by 9
Of the ten digits, 0 is the only one that is divisible by 9.
The least three-digit number that is divisible by both 5 and 9 is 135.
All 4 digit numbers that are divisible by 9 are also divisible by 3. The first is 1008 and the last is 9999.
All you need to do is multiply the three numbers together:5 * 6 = 3030 * 9 = 270
48. Assuming no digit can be used more than once, the two digit numbers divisible by 4 are: 16, 36, 48, 56, 64, 68, 84, 96 8 of them. For any number to be divisible by 4, only the last two digits need be divisible by 4; so for three digit numbers, each of the two digit numbers above can be preceded by any of the remaining 5 digits and still be divisible by 4. → 5 x 8 = 40 three digit numbers are divisible by 4 → 40 + 8 = 48 two or three digit numbers made up of the digits {1, 3, 4, 5, 6, 8, 9} are divisible by 4. If repeats are allowed, there are an extra 2 two digit numbers (44 and 88) and each of the two digit numbers can be preceded by any of the 7 digits, making a total of 7 x 10 + 10 = 80 two and three digits numbers divisible by 4 make up of digits from the given set.
144 is divisible by 12 and 9.
180
900
225