Un cero a la izquierda

I learned the most charming Spanish idiom this week from Juan, my Puerto Rican buddy with whom I volunteer as a Spanish interpreter at the Rotacare Free Clinic: "Ser un cero a la izquierda", whose literal translation is "to be a zero to the left". In our mathematical notation system, of course, placing a zero to the left---typically only done before a decimal point---does nothing to change the value of the number. Hence, a person who is un cero a la izquierda is someone who is useless, or of no account.