a cup in metric terms is 250 ml. 2/3 of 250 ml = 166.6 ml. so. there you go? hope this helps?
http://wiki.answers.com/Q/What_is_two_thirds_in_cu...

1. Measure 2/3cup of a liquid ingredient by pouring the liquid into a 1cup glass measuring cup. Find the line on the side of the measuring cup before you begin pouring so you know
http://www.ehow.com/how_8235440_measuretwothirds...

To figure out what is one half of two thirds I convert it to decimals. Two thirds is .666 and 1/2 is .5. Then I take .666 and multiply it by .5. The answer is .333 or 1/3.
http://answers.ask.com/Health/Diseases/what_is_one...

Half of two thirds cup is one third (1/3) cup. Just divide 2/3 by 2. Call
http://www.chacha.com/question/whatishalfoftwo...
