"mas" al igual que todos los monosílabos no deben llevar tilde. Es una regla ortográfica It's an orthographic rule that says: monosyllables don't have to use TILDE

más without tilde dont exist i think. I hope help u :)

The answer of Danny is correct. I just want to add, that the use of "mas" is a cultism, unusual when you're speaking. But "mas" y "pero" means the same. "Mas" está en desuso en la lengua hablada, en la lengua escrito es un cultismo, cada vez menos usado. Significa lo mismo que "pero"

Even THOUGH (aunque) You are bad sometimes I love You anyway BUT (pero) You need to change your behavior a little bit....

"Aunque" means "although" or "even though", or sometimes "even if", while "pero" means "but". "Mas" (without the tilde) usually means the same as "pero". Espero haberte ayudado!