Вычислите дроби: 1/9+4/9; 7/8-3/8; 15/19-6/19; 5/16+1/16; 3/14+11/14; 11 /21+ 4/21

1) 1/9 + 4/9 = 5/9 (0,5)
2) 7/8 - 3/8 = 4/8 = 1/2
3) 15/19 - 6/19 = 9/19
4) 5/16 + 1/16 = 6/16 = 3/8
5) 3/14 + 11/14 = 14/14 = 1
6) 11/21 + 4/21 = 15/21 = 5/7