When would there be only four different equations for a set of math mountain numbers

When the two numbers at the bottom are the same. Example: 40, 40, 80

I hope this helps you :)

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.