PLEASE HELP!! I'm taking the SAT2 in the next few hours

<p>I need some help on the SAT2 chem. test.</p>

<p>for acids/bases, how do you change a H30 to a pH or a OH to a pOH without a calculator???</p>

<p>For example can u solve this:</p>

<p>change 1.35 * 10^-3 to a pOH?
i put in -log(1.35 * 10^-3)
the correct answer from the caluculator is 2.87.</p>

<p>HOW WOULD I DO THIS WITHOUT A CALCULAOR??? IS IT EVEN POSSIBLE TO DO NEGATIVE LOGS IN YOUR HEAD???</p>

<p>PLEASE I NEED AN ANSWER, I'LL BE TAKING THE REAL TEST IN THE NEXT FEW HOURS!!!</p>

<p>THANKS</p>

<p>Why aren't you sleeping???</p>