You're right.

"...I knew a woman, she could multiply and divide, and calculate the square root by abacus..."

As a child, I could count on them. My grandmother was the chief economist of the military factory and taught me this. But I no longer liked to ride them with other children. If they flip down swivel casters, and put them on top of a piece of plywood, then they turn into a great machine, where you can sit and ride.

However, it quickly breaks down such use :)