1) 2 5/7 - 1.3/5 =19/7 - 8/5 = (19*5 -8*7)/35 = 39/35
2) 39/35 : 1,3 =39/35 * 10/13= ( 39*10) / (35 * 13) =(3 *2) /(7*1) = 6/7
3) 1. 3/7 * 0,25 = 10 /7 * 1/4 = 10/28 = 5/14
4) 6/7 - 5/14 =( 6*2 -5)/14 = 7/14 =1/2
5)( 2/5 -7/18) * 15 = (2/5 * 15 ) - (7/18 *15) = ((2*15)/5 ) - ((7*15)/18) =
= 6- (35 /6) = 6 - 5.5/6 = 1/6
6) 1/2 : 1/6 =1/2 * 6/2 = 6/2 =3