How many legs are on the bus?

Ooh-la la I thought, something to pass the time.

There is a bus with seven children inside, each child has seven bags. Inside each bag there are seven big cats. Each big cat has seven small cats. All cats have four legs each.
How many legs are on the bus?

I got my calculator at the ready and my yellow post-it notes to start methodically scribbling my calculations:

7 x 7 = 49 bags
49 x 7 = 343 cats
343 x 4 = 1372 cat legs
7 x 2 = 14 child legs
1372 + 14 = 1356 legs in total

Imagine my disappointment when the answer was revealed;

None as the bus has wheels not legs.

Moral of the story; Legs are a proven distraction.
All I want to know is if my leggy Maths is correct(!) otherwise I’m going to look like even more of a fanny Adams.