А) 3/10 : 30 = 3/10 * 1/30 = (1*1)/(10*10) = 1/100 = 0,01
б) 1 5/7 : 3 3/4 = 12/7 : 15/4 = 12/7 * 4/15 = (4*4)/(7*5) = 16/35
в) 5 1/2 : 2 1/5 = 11/2 : 11/5 = 11/2 * 5/11 = 5/2 = 2 1/2 = 2,5
г) 4 1/2 : 3 3/4 = 9/2 : 15/4 = 9/2 * 4/15 = (3*2)/(1*5) = 6/5 = 1 1/5 = 1,2
д) 2 3/5 : 2 4/11 = 13/5 : 26/11 = 13/5 * 11/26 = (1*11)/(5*2) = 11/10 = 1 1/10 = 1,1