5 1/3-6 1/4=5*3+1/3-6*4+1=16/3*25/4=16/3-25/4=16/3*4/4-25/4*3/3=64/12-75/12=64-75/12=-11/12
-3 2/9*3= -3*9+2/9 *3*3+0/3=29/9*9/3=-29*9/9*3=-261/27= -29*9/3*9=-2+9*3/3=-9 2/3
-3 1/2 *(-1 3/7)= -3 1/2 *-1 3/7=-3*2+1/2*-1*7+3/3=-7/2*-10/7=-7/2*-10/7=70/14=-5/1*14/14=0+5*1/1=5 0/1