Johnny is out walking his two dogs at night, and his son joins him for the walk.  How many legs' worth of organisms are traveling together for this walk?
As Johnny and his son are humans, and humans walk on two legs, this means that between the two of them there are 2*2=<<2*2=4>>4 legs' worth of organisms.
There are two dogs walking along as well, and since dogs walk on 4 legs this means there are 2*4=<<2*4=8>>8 legs' worth of organisms.
We add these two totals together to find there are 4+8=<<4+8=12>>12 legs' worth of organisms in total.
#### 12