What is the easiest song to sing with just a piano/keyboard?

I sing all sorts of different song styles but atm i've been asked to sing with just a keyboard. But we don't know what song to sing. So does anybody have any ideas about songs that are easy to play on the keyboard and preferably able to learn in approximately 4 days? Thanks

What is a VPN?

VPN is (Virtual Private Network) were first used by companies to enable their employees to securely access internal systems such as email remotely (e.g. from home or while on business trips). Today they are increasingly being used for personal use by individuals to protect their privacy while online in public places (e.g. when using the wi-fi connection in a cafe) or in a country where the internet is censored / blocked (e.g. China, Saudi Arabia��).