1) 1/2 = 5*1/2*5 = 2/10 = 0,5;  1/4 = 1*25/4*24 = 25/100 =0,25 ;  1/5 = 2*1/2*5 = 2/10 =0,2 ;  1/20 = 1*5/20*5 = 5/100 =0,05;  1/25 = 1*4/25*4 = 4/100 =0,04;  1/50 = 2*1/50*2 = 2/100 = 0,022) 3/4 = 3*25/4*25 = 75/100 = 0,75;  2/5 = 2*2/5*2 = 4/10 = 0,4; 3/20 = 3*5/20*5 = 15/100 = 0,15;  2/25 = 2*4/25*4 = 8/100 = 0,08;  3/50 = 3*2/50*2 = 6/100 = 0,06;  3) 2.1/2 = 21/10/2 = 21/20 = 21*5/20*5 = 105/100 = 1,05;   3.1/4 = 31/10/4 = 31/40 = 31*5/40*5 = 155/200 = 77,5 /100 = 0,775;  1.7/20 = 17/10/20 = 17/200 = 8,5/100 = 0,085;  4.4/25 = 44/10/25 = 44/250 = 1,76/10  = 0,176;  4) 3/2 = 3*5/2*5 = 15/10 = 1,5 ;  9/4 = 9*25/4*25 = 225/100 = 2,25 ;  63/20 = 63*5/20*5 = 315/100 = 3,15;   51/25 = 51*4/25*4 = 204/100 = 2,04;