(х-3)/4 +(х+1)/4=(х-3-х+1)/4= -2/4= - 1/2
(m+n)/a -(m-n)/a=(m+n-m+n)/a=2n/a
(5x+1)/2 - x/2=(5x+1-x)/2=(4x+1)/2=(2(2x+0.5))/2=2x+0.5
(x-1)/4 +(x+2)/4 -(x-3)/4=(x -1+x+2-x+3)/4=( -x+4)/4=(4-x)/4
(3p-2q)/m - (p-q)/m=(3p-2q-p+q)/m=(2p - 3q)/m
(2a+1)/b +(3a+1)/b - (a-2)/b=(2a+1+3a+a-a+2)/b=(5a +3)/b