



 
Hi John.
Buses have no legs and children of 2 each, so there are 2x7 child legs.
There are 7 children times 7 rucksacks per child, so there are 7x7 rucksacks. Rucksacks have no legs, though.
There are 7x7 rucksacks times 7 big cats per rucksack, for a total of 7x7x7 big cats. Each big cat has 4 legs, so there are 4x7x7x7 big cat legs.
Assuming those small cats are in the rucksacks with the big cats, there are 7x7x7 big cats with 7 small cats per big cat, so there are 7x7x7x7 small cats, each with 4 legs. That makes 4x7x7x7x7 small cat legs. So the total number of legs equals 2x7 child legs + 4x7x7x7 big cat legs + 4x7x7x7x7 small cat legs. Warning: if you see a school bus like this, for your own safety do not approach it! Cheers,  


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