Сравните дроби, приведя их к общему знаменателю: а) 1/5 и 1/20

а) 1/5 и 1/20 = (1 * 4)/(5 * 4) и 1/20 = 4/20 и 1/20;
4/20 gt; 1/20.

б) 2/13 и 4/11 = (2 * 11)/(13 * 11) и (4 * 13)/(11 * 13) = 22/143 и 52/143;
22/143 lt; 52/143.

в) 7/20 и 10/15 = (7 * 3)/(20 * 3) и (10 * 4)/(15 * 4) = 21/60 и 40/60;
21/60 lt; 40/60.

г) 3/8 и 9/20 = (3 * 5)/(8 * 5) и (9 * 2)/(20 * 2) = 15/40 и 18/40;
15/40 lt; 18/40.

д) 5/7 и 19/2 = (5 * 2)/(7 * 2) и (19 * 7)/(2 * 7) = 10/14 и 133/14;
10/14 lt; 133/14.