1) (-2/15)-(-7/5)=(-2/15)+(7*3)/*5*3)=(-2/15)+(21/15)=(-2+21)/15=19/15=1 4/15
2) (-1 3/8)-(1/4)=(-(1*8+3)/8)-(1*2)/(4*2)=(-11/8)-(2/8)=(-11-2)/8=-13/8=-1 5/8
3) 1 5/11-2 3/22=(1*11+5)/11-(2*22+3)/22=16/11-47/22=(16*2)/(11*2)-47/22=
=32/22-47/22=(32-47)/22=-15/22