Сравнить дроби, найти их суммы и разности:

1) 13/20 и 7/20: 13/20 > 7/20; 13/20 + 7/20 = 20/20 = 1; 13/20 - 7/20 = 6/20 = 3/10 2) 4/15 и 8/15: 4/15 < 8/15; 4/15 + 8/15 = 12/15 = 4/5; 8/15 - 4/15 = 4/15 3) 13/19 и 15/19: 13/19 < 15/19; 13/19 + 15/19 = 28/19 = 1 9/19; 15/19 - 13/19 = 2/19 4) 5/11 и 3/11: 5/11 > 3/11; 5/11 + 3/11 = 8/11; 5/11 - 3/11 = 2/11 5) 1 5/12 и 5/12: 1 5/12 > 5/12; 1 5/12 + 5/12 = 1 10/12 = 1 5/6; 1 5/12 - 5/12 = 1 6) 15/61 и 9/61: 15/61 > 9/61; 15/61 + 9/61 = 24/61; 15/61 - 9/61 = 6/61 7) 7/33 и 28/33: 7/33 < 28/33; 7/33 + 28/33 = 35/33 = 1 2/33; 28/33 - 7/33 = 21/33 = 7/11 8) 4/27 и 18/27: 4/27 < 18/27; 4/27 + 18/27 = 22/27; 18/27 - 4/27 = 14/27 9) 19/25 и 13/25: 19/25 > 13/25; 19/25 + 13/25 = 32/25 = 1 7/25; 19/25 - 13/25 = 6/25 10) 7 2/7 и 1 3/7: 7 2/7 > 1 3/7; 7 2/7 + 1 3/7 = 8 5/7; 7 2/7 - 1 3/7 = 6 9/7 - 1 3/7 = 5 6/7 11) 29/103 и 28/103: 29/103 > 28/103; 29/103 + 28/103 = 57/103; 29/103 - 28/103 = 1/103 12) 107/152 и 213/152: 107/152 < 213/152; 107/152 + 213/152 = 320/152 = 40/19 = 2 2/19; 213/152 - 107/152 = 106/152 = 53/76 13) 15/143 и 29/143: 15/143 < 29/143; 15/143 + 29/143 = 44/143 = 4/13; 29/143 - 15/143 = 14/143 14) 11/201 и 5/201: 11/201 > 5/201; 11/201 + 5/201 = 16/201; 11/201 - 5/201 = 6/201 = 2/67 15) 1 1/9 и 2 4/9: 1 1/9 < 2 4/9; 1 1/9 + 2 4/9 = 3 5/9; 2 4/9 - 1 1/9 = 1 3/9 = 1 1/3