If you know the LCM then you divide it by the other number. If you don't already know it: is 8 a factor of 9 or do they have equal factors? No. Is 9 a factor of 8 or do they have equal factors? No. The easy way: multiply 8 by 9 to get LCM :)
This can lead to cyclical patterns of predator and prey abundance, where prey increase in number and then, with abundant food, predator number increases ...
