Because if they did, they would have done during lessons to learn it, sweetie

Thanks for calling me a sweetie. Love u too. Forgetting is a thing. Unlike previous generations they are not as much exposed to analog ones. Therefore they don't need to. Digital clocks are used in electronic devices etc.

They also know how to use calculator, they just don't knot 2 times 2 is four without it. Neither have place during an exam

Except basic math is necessary since the brain is faster with smaller calculations and analog clock really isn't that much necessary anymore. They can be replaced.