Привидите к общему знамеенателю (800,801) 1/10 и 1/15, 1/10 и 1 /25, 1/30 и 1/40, 1/30 и 1/50
1) 1/10 и 1/15 = 3/30 и 2/30 ; 1/10 и 1/25 = 5/50 и 2/50; 1/30 и 1/40 = 4/120 и 3/120; 1/30 и 1/50 = 5/150 и 3/150.