[5/2-(7/9-11/12+1/6)*36]*1/5
=[5/2-7/9*36+11/12*36-1/6*36]*1/5
=(5/2-28+33-6)*1/5
=(5/2-1)*1/5
=5/2*1/5-1*1/5
=1/2-1/5
=3/10