This would be the least common multiple of 3, 4, 5, and 9. We can start by listing the multiples of the biggest number, 9, and seeing if each of the numbers can be divisible by the smaller numbers.
9: 9, 18, 27, 36, 45, 54, 63, 72, 81, 90, 99, 108, 117, 126, 135, 144, 153, 162, 171, 180
180 would be the answer because it is the first number in our list that is divisible by 3, 4, 5, and 9.
