There are over 2700 species of snakes in the world over 600 are venomous express the fraction of species that are not venomous as a desimal

You do 600 divided by 2700 and you end up with 22/100 or 0.22 as a decimal. So if 0.22 or 22/100 are venimous then 78/100 or 0.78 are non venimous. I understand its a bit confusing and i can simplify it for you but still I hope this helps :)