Tipping in the USA and complex calculations

This is a small detail of everyday life that bothers most Europeans people. The service is not included in the United States, you need, when the bill arrive, calculating a tip every time you'll leave on the table (about 20%).
But this practice is now being challenged in ceertains restaurants.

When I'll go in the USA, I won't forget my calculator

Hi Florent,

Yers, you're right, it's a nightmare... by the way, reading your message I'm not sure to always have thought of it.

I see you post easily in English now... are you taking lessons?

No, no lessons; but I meet a person speaking english, that's why I need to brush up

> I meet a person speaking english
The best class!