N1 а) 42/39х1/42х39/60=... б) 101/102х102/103х103/104=... в) 3/8х8/13х13/18=... N2 а) 25х7/30=... б) 32х11/48=... в) 13/15х6=... г) 7/20х15=...

№1. 42/39 * 1/42* 39/60 = (42*1*39) /(39*42*60)= (1*1*1)/(1*1*60) = 1/60 101/102 *  102/103 * 103/104 = (101*102*103)/ (102*103*104) = = (101*1*1)/(1*1*104) = 101/104 3/8 *8/13 * 13/18 = (3*8*13)/ (8*13*18) = (1*1*1)/(1*1*6)= 1/6 №2. 25  *  7/30  = 25/1  *  7/30 = (25*7)/(1*30)= =(5*7)/ (1*6) = 35/6 = 5 5/6 32  *  11/48 = (32*11)/(1*48) =  (2*11) /( 1*3) = = 22/3=  7  1/3 13/15  * 6  =  (13*6)/(15*1)= (13*2)/ (5*1) =  = 26/5 = 5  1/5 7/20  * 15  = (7*15)/ (20*1) = ( 7*3)/(4*1)= = 21/4 = 5  1/4