You have to find the lowest number that goes into both 2 and 6. The lowest number that can go into both 2 and 6 evenly (1 isn't an option) is 2. 2 goes into 2 once and into 6, 3 times. So you change the 2 to 1 and the 6 to 3 making the new fraction 1/3 which is the simplest form of 2/6.