Assuming each dimension must be an integer, how many different rectangular prisms with a volume of 18cm3 are there?

Answer is 4: 1*1*18, 1*2*9, 1*3*6, 2*3*3 BUT what happened to 1*18*1, or 2*9*1 they are different from the previous ones right?

Thank you 🙂

No, they’re not different. They’re just the same prisms turned in a different orientation. Think about it like Tetris—you can turn a block a few different ways to suit your needs, but it’s always the same block.