6класс , вычислите: а) 2/5 / 34 б) 3/7 / 2/5 в) 6/11 / 3/11 г) 13/5 / 25/15

а) 2/5 / 34  =  2/5 : 34 = 2/5 * 1/34 = 1/5 * 1/17 = 1/85 
б) 3/7 / 2/5 = 3/7 : 2/5 = 3/7 * 5/2 = 15/14 = 1 1/14
в) 6/11 / 3/11 = 6/11 : 3/11 = 6/11 * 11/3 = 2
г) 13/5 / 25/15 = 13/5 : 25/15 = 15/5 * 15/25 = 3/1 * 3/5 = 9/5 = 1 4/5

2/5:34=2/5:34/1=2/5*1/34=1/85
3/7:2/5=3/7*5/2=15/14=1 1/14
6/11:3/11=6/11*11/3=2
13/5:25/15=13/5*15/25=39/25=1 14/25