7 1/2 + 1/4; б 3 1/4+ 2/3 ;в 2 4/9 +1 1/3

3,5+0,25=3,75 13/4+2/3=39/12+8/12=47/12=3 11/12 22/9+11/3=22/9+33/9=55/9=6 1/9