12 times 1 times 12
There is only one three digit number for a gross, and that is 144.
144
144
144 is divisible by 12 and 9.
A three-digit number that is divisible by both three and four must also be divisible by their least common multiple, which is twelve. The smallest three-digit number divisible by twelve is 108, and the largest is 996. Therefore, any three-digit number that is a multiple of twelve, such as 120, 144, or 480, will meet the criteria of being divisible by both three and four.
Three numbers that fit these criteria are:108, 144, and 180.
108 117 126 135 144 153 and 162
144
24
144 / 3 = 48
115/16 - 28/9 = 1035/144 - 448/144 = 587/144 = 4 and 11/144
144, 324, 576 and 900 are even three-digit square numbers that are multiples of 3.