Question 617338
Good, so 2/3 + 3/4 = 17/12 (the terms that change are in <font color="blue">blue</font> and change to what's shown in <font color="green">green</font>)


1/2 + <font color="blue">(2/3 + 3/4)</font> - (4/5 * 5/6)


1/2 + <font color="green">17/12</font> - (4/5 * 5/6)


Now keep going...


1/2 + 17/12 - 20/30


1/2 + 17/12 - 2/3


6/12 + 17/12 - 8/12


(6+17-8)/12


15/12


5/4


So 1/2 + (2/3 + 3/4) - (4/5 * 5/6) = <font color="red">5/4</font>