привести подобные слагаемые:
a) 1/12m-1/4m-1/3m;

b) c-0,8c-1/5c-1/2c;

c) 2/3a+3/8b-1/6a-1/4b;

d) 0,2m-2/9-4m+5/9;

a)1/12m-3/12m-4/12m=-6/m=-0,5mb)c-0,8c-0,2c-0,5c=-0,5cc) 4/6a-1/6a+3/8b-2/8b=3/6a+1/8b=1/2a+1/8bd) -3,8m+3/9=-3,8m+1/3